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Created page with 'Category:Fall 2015 SPO600 {{Admon/important|It's Alive!|This SPO600 weekly schedule will be updated as the course proceeds - dates and content are subject to change. The …'
[[Category:Fall 2015 SPO600]]
{{Admon/important|It's Alive!|This [[SPO600]] weekly schedule will be updated as the course proceeds - dates and content are subject to change. The cells in the summary table will be linked to relevant resources and labs as the course progresses.}}
For the Winter 2015 version of the weekly schedule, see [[Winter 2015 SPO600 Weekly Schedule]].
== Schedule Summary Table ==
This is a summary/index table. Please follow the links in each cell for additional detail -- especially for the ''Deliverables'' column.
{|cellspacing="0" width="100%" cellpadding="5" border="1" style="background: #e0e0ff"
|-
!Week!!Week of...!!Tuesday!!Thursday!!Deliverables<br/>(Summary - click for details)
|-
|1||Jan 12||[[#Tuesday (Jan 13)|Introduction to Software Porting, Portability, Benchmarking, and Optimization / How is code accepted into an open source project? (Lab 1)]]||[[#Thursday (Jan 15)|Benchmarking and Profiling]]||[[#Week 1 Deliverables|Set up accounts, and blog a comparision of code reviews in two communities (Lab 1).]]
|-
|2||Jan 19||[[#Tuesday (Jan 20)|Working with the code / Building]]||[[#Thursday (Jan 22)|Build and benchmark a portion of the LAMP stack (Lab 2)]]||[[#Week 2 Deliverables|Blog about your baseline data (Lab 2)]]
|-
|3||Jan 26||[[#Tuesday (Jan 27)|Profiling: Finding the pain points (Lab 3)]]||[[#Thursday (Jan 29)|Computer architecture overview]]||[[#Week 3 Deliverables|Blog about the profiling results and pain points discovered (Lab 3)]]
|-
|4||Feb 2||[[#Tuesday (Feb 3)|Compiled C Lab (Lab 4)]]||[[#Thursday (Feb 5)|Compiler optimizations]]||[[#Week 4 Deliverables|Blog a commentary on the Compiled C Lab (Lab 4).]]
|-
|5||Feb 9||colspan="2" align="center"|Linaro Connect - No classes scheduled<br />[[#Week 5|'''Prepare a presentation on a selected topic about platform-specific code.''']]||[[#Week 5 Deliverables|Be prepared to present your topic.]]
|-
|6||Feb 16||[[#Tuesday (Feb 17)|Presentations on platform-specific code.]]||[[#Thursday (Feb 19)|Presentations on platform-specific code.]]||[[#Week 6 Deliverables|Blog about your presentation.]]
|-
|7||Feb 23||[[#Tuesday (Feb 24)|Assembly lab (Lab 5)]]||[[#Thursday (Feb 26)|Inline assembly lab and Course Projects]]||[[#Week 7 Deliverables|Blog about the Assembly Lab (Lab 5) and start project investigation.]]
|-style="background: #f0f0ff"
|Study Week||Mar 2||colspan="3" align="center"|Study Week - No classes! Please work on your initial project investigation.
|-
|8||Mar 9||[[#Tuesday (Mar 10)|Project discussion, and Reading Reference Documentation.]]||[[#Thursday (Mar 12)|Project presentations - Stage 1]]||[[#Week 8 Deliverables|Blog about your project progress - this will be used to assign your 1st Project marks.]]
|-
|9||Mar 16||[[#Tuesday (Mar 17)|Upstreaming]]||[[#Thursday (Mar 19)|Spinlocks and Tail Call Optimization]]||[[#Week 9 Deliverables|Blog about your project work.]]
|-
|10||Mar 23||[[#Tuesday (Mar 24)|Portable alternatives to Assembler]]||[[#Thursday (Mar 26)|Project Presentations - Stage 2]]||[[#Week 10 Deliverables|Blog about your project progress - this will be used to assign your 2nd Project Marks.]]
|-
|11||Mar 30||[[#Tuesday (Mar 31)|Hack Session]] (Professor will not be present)||[[#Thursday (Apr 2)|SIMD]]||[[#Week 11 Deliverables|Blog about SIMD/vectorization and your project.]]
|-
|12||Apr 6||[[#Tuesday (Apr 7)|Discussion & Hack Session]]||[[#Thursday (Apr 9)|Vectorization]]||[[#Week 12 Deliverables|Blog about your work.]]
|-
|13||Apr 13||[[#Tuesday (Apr 14)|Project Presentations - Stage 3]]||[[#Thursday (Apr 16)|Wrap-up Session]]||[[#Week 13 Deliverables|Blog about your project progress - this will be used to assign your 3rd project marks.]]
|-
|-style="background: #f0f0ff"
|Exam Week||Apr 20||colspan="3" align="center"|Exam Week - No exam in this course!
|}
== Evaluation ==
{|cellspacing="0" width="100%" cellpadding="5" border="1" style="background: #e0ffe0"
!Category!!Percentage!!Evaluation Dates
|-
|Communication||align="right"|20%||January 31, February 28, March 27, April 22
|-
|Quizzes||align="right"|10%||May be held during any class, usually at the start of class. A minimum of 5 one-page quizzes will be given. No make-up/retake option is offered if you miss a quiz. Lowest 3 scores will not be counted.
|-
|Labs||align="right"|10%||See deliverables column above.
|-
|Project work||align="right"|60%||March 16 (15%), March 31 (20%), April 22 (25%)
|}
== Week 1 ==
=== Tuesday (Jan 13) ===
==== Introduction to the Problems ====
===== Porting and Portability =====
* Most software is written in a '''high-level language''' which can be compiled into [[Machine Language|machine code]] for a specific computer architecture. In many cases, this code can be compiled for multiple architectures. However, there is a lot of existing code that contains some architecture-specific code fragments written in [[Assembly Language]] (or, in some cases, machine-specific high-level code).
* Reasons for writing code in Assembly Langauge include:
** Performance
** [[Atomic Operation|Atomic Operations]]
** Direct access to hardware features, e.g., CPUID registers
* Most of the historical reasons for including assembler are no longer valid. Modern compilers can out-perform most hand-optimized assembly code, atomic operations can be handled by libraries or [[Compiler Intrinsics|compiler intrinsics]], and most hardware access should be performed through the operating system or appropriate libraries.
* A new architecture has appeared: Aarch64, which is part of [http://www.arm.com/products/processors/instruction-set-architectures/armv8-architecture.php ARMv8]. This is the first new [[Computer Architecture|computer architecture]] to appear in several years (at least, the first mainstream computer architecture).
* At this point, most key open source software (the software typically present in a Linux distribution such as Ubuntu or Fedora, for example) now runs on AArch64. However, it may not run as well as on older architectures (such as x86_64).
===== Benchmarking and Profiling =====
Benchmarking involves testing software performance under controlled conditions so that the performance can be compared to other software, the same software operating on other types of computers, or so that the impact of a change to the software can be gauged.
Profiling is the process of analyzing software performance on finer scale, determining resource usage per program part (typically per function/method). This can identify software bottlenecks and potential targets for optimization.
===== Optimization =====
Optimization is the process of evaluating different ways that software can be written or built and selecting the option that has the best performance tradeoffs.
Optimization may involve substituting software algorithms, altering the sequence of operations, using architecture-specific code, or altering the build process. It is important to ensure that the optimized software produces correct results and does not cause an unacceptable performance regression for other use-cases, system configurations, operating systems, or architectures.
The definition of "performance" varies according to the target system and the operating goals. For example, in some contexts, low memory or storage usage is important; in other cases, fast operation; and in other cases, low CPU utilization or long battery life may be the most important factor. It is often possible to trade off performance in one area for another; using a lookup table, for example, can reduce CPU utilization and improve battery life in some algorithms, in return for increased memory consumption.
Most advanced compilers perform some level of optimization, and the options selected for compilation can have a significant effect on the trade-offs made by the compiler, affecting memory usage, execution speed, executable size, power consumption, and debuggability.
===== Build Process =====
Building software is a complex task that many developers gloss over. The simple act of compiling a program invokes a process with five or more stages, including pre-proccessing, compiling, optimizing, assembling, and linking. However, a complex software system will have hundreds or even thousands of source files, as well as dozens or hundreds of build configuration options, auto configuration scripts (cmake, autotools), build scripts (such as Makefiles) to coordinate the process, test suites, and more.
The build process varies significantly between software packages. Most software distribution projects (including Linux distributions such as Ubuntu and Fedora) use a packaging system that further wraps the build process in a standardized script format, so that different software packages can be built using a consistent process.
In order to get consistent and comparable benchmark results, you need to ensure that the software is being built in a consistent way. Altering the build process is one way of optimizing software.
Note that the build time for a complex package can range up to hours or even days!
==== Course Projects ====
In this course, you will:
# Test the performance of all or part of the LAMP stack.
# Determine how the performance of one specific part of the stack could be improved, either specifically on AArch64 systems (without detriment to other systems) or on all systems.
# Prepare a fix/patch for the software to implement that performance improvement.
# Prove that your changes do not cause any unacceptable performance regressions (Note: there might be performance regressions which are considered acceptable!).
# Upstream your Code - Submit your code to the upstream (originating) software project so that it can be incorporated into future versions of the software. This will involve going through a code review to ensure that your code is compatible with and acceptable to the upstream community.
==== General Course Information ====
* Course resources are linked from the CDOT wiki, starting at http://zenit.senecac.on.ca/wiki/index.php/SPO600 (Quick find: This page will usually be Google's top result for a search on "SPO600").
* Coursework is submitted by blogging.
* Quizzes will be short (1 page) and will be held without announcement at any time. Your lowest three quiz scores will not be counted, so do not worry if you miss one or two.
* Course marks (see Weekly Schedule for dates):
** 60% - Project Deliverables
** 20% - Communication (Blog and Wiki writing)
** 20% - Labs and Quizzes (10% labs - completed/not completed; 10% for quizzes - lowest 3 scores not counted)
* All classes will be held in an [[Active Learning Classroom]] -- you are encouraged to bring your own laptop to class. If you do not have a laptop, consider signing one out of the Learning Commons for class, or using a smartphone with an HDMI adapter.
* For more course information, refer to the SPO600 Weekly Schedule (this page), the [http://www.senecacollege.ca/ssos/findWithoutSemester/spo600/sict Course Outline], and [[SPO600 Course Policies]].
<!-- * Introduction to the [http://linaro.org Linaro] Code Porting/Optimization project. -->
<!-- * Optional: You can participate in the [http://linaro.org Linaro] Code Porting/Optimization contest. For details, see the [http://www.youtube.com/watch?v=Lo1dBB3tke8 YouTube video] of Jon "maddog" Hall and Steve Mcintyre at Linaro Connect USA 2013. -->
==== Discussion of how open source communities work ====
* Background for the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
=== Thursday (Jan 15) ===
* Benchmarking
* Profiling
=== Week 1 Deliverables ===
# Set up your [[SPO600 Communication Tools]] - in particular, set up a blog and add it to [http://zenit.senecac.on.ca/~chris.tyler/planet/ Planet CDOT] (via the [[Planet CDOT Feed List]]).
# Add yourself to the [[Winter 2015 SPO600 Participants]] page (leave the projects columns blank).
# Generate a [[SSH#Using_Public_Keys_with_SSH|pair of keys]] for [[SSH]] and email the public key to your professor.
# Sign and return the [[Open Source Professional Option Student Agreement]].
# Optional but recommended: [[SPO600 Host Setup|Set up a personal Fedora system]].
== Week 2 ==
=== Tuesday (Jan 20) ===
{{Admon/tip|Bring Your Laptop|Classes are held in a [[Active Learning Classroom]]. If you have a laptop or other device with a VGA or HDMI output (such as a smartphone!) please bring it. You'll need either a local linux environment or an [[SSH]] client -- which is built-in to Linux, Mac, and Chromebook systems, and readily available for Windows, Android, and iOS devices.}}
Status Check
* Introductions around the Room
** Name
** Program
** Interest in the course
** Results of <code>gzip</code> benchmarking and most interesting thing you observed
* Check the [[SPO600 Servers|server accounts]] that were set up with your [[SSH]] keys
* Sheets from Last Week
** Open Source Student Agreement
** Survey (Optional)
Working with the Code
* Getting Code
** In a tarball
** From git
*** Git basics
** Working with other version control systems
* Building the Code
** Make
** Configuration tools (autotools, cmake)
** The compiler toolchain
*** Preprocessor
*** Compiler
*** Assembler
*** Linker
** Debug vs. Non-debug/Stripped binaries
Looking at How Distributions Package the Code
* Using fedpkg
==== Resources ====
* [https://sourceware.org/binutils/docs-2.16/gprof/ GProf Manual]
* [http://www.thegeekstuff.com/2012/08/gprof-tutorial/ Profiling with GProf]
=== Thursday (Jan 22) ===
* [[SPO600 Baseline Builds and Benchmarking Lab|Baseline Builds and Benchmarking Lab (Lab 2)]]
=== Week 2 Deliverables ===
* Complete and blog your conclusion to the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
* Blog your baseline data from the [[SPO600 Baseline Builds and Benchmarking Lab|Baseline Builds and Benchmarking lab (Lab 2)]].
== Week 3 ==
=== Tuesday (Jan 27) ===
Profiling
* Profiling with <code>gprof</code>
** Build with profiling enabled (use the option <code>-pg</code> with both gcc and ld)
** Run the profile-enabled executable
** Analyze the data in the <code>gmon.out</code> file
*** <code>gprof ''nameOfBinary''</code> # Displays text profile including call graph
*** <code>gprof ''nameOfBinary'' | gprof2dot | dot | display -</code> # Displays visualization of call graph
* Other profiling tools
** OProf, SystemTap, and others
* [[SPO600 Profiling Lab]] (Lab 3)
=== Thursday (Jan 29) ===
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
=== Week 3 Deliverables ===
* Complete and blog your conclusions to the [[SPO600 Profiling Lab|Profiling Lab (Lab 3)]].
== Week 4 ==
=== Tuesday (Feb 3) ===
* [[SPO600 Compiled C Lab|Compiled C Lab (Lab 4)]]
=== Thursday (Feb 5) ===
* [[Compiler Optimizations]]
=== Week 4 Deliverables ===
* Blog your [[SPO600 Compiled C Lab|Compiled C Lab (Lab 4)]] results. Be sure to include a reflective section on what you learned.
* Select your topic for the [[Winter 2015 SPO600 Platform Specific Code Presentation|Platform-Specific Code Presentation]].
== Week 5 ==
* Prepare your [[Winter 2015 SPO600 Platform Specific Code Presentation|Platform-Specific Code Presentation]].
=== Week 5 Deliverables ===
* Be ready to [[Winter 2015 SPO600 Platform Specific Code Presentation|present]].
== Week 6 ==
=== Tuesday (Feb 17) ===
* Introduction to the [http://www.96boards.org/products/hikey/ HiKey] board and the [http://www.96boards.org/ 96Boards] project.
* [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
=== Thursday (Feb 19) ===
* [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
=== Week 6 Deliverables ===
* Blog about your presentation.
== Week 7 ==
=== Tuesday (Feb 24) ===
* [[SPO600 Assembler Lab|Assembly language lab (Lab 5)]]
=== Thursday (Feb 26) ===
* Remaining [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
* [[Inline Assembly Language]]
* [[Winter 2015 SPO600 Project|Course Projects]]
=== Week 7 Deliverables ===
* Blog your conclusion to the [[SPO600 Assembler Lab|assembly language lab (Lab 5)]] - See the ''Deliverables'' section in the lab instructions for details on what to include in your blog post.
== Week 8 ==
=== Tuesday (Mar 10) ===
* Project discussion
** Discussion of project ideas and fine-tuning of project plans
** Next steps
** Addressing Problem Areas
* Accessing and Reading Reference Documentation
** AArch64 ISA
=== Thursday (Mar 12) ===
* Project presentations
** Provide a very short (2 minute) overview of your project. Include:
*** Which piece of software you are working on
*** What area of that software needs optimization/performance tuning
*** How you are going to perform the optimization/tuning (algorithm replacement, platform-specific code, removing platform-specific code, build options, and so forth)
*** Plans for the next step
*** Engagement with the upstream community
* Use this project presentation to tell the class what you're working on and incorporate feedback into your blog post
=== Week 8 Deliverables ===
* Blog about your project and plans, incorporating feedback from your presentation
* Add your project to the [[Winter 2015 SPO600 Participants|Participants and Project Table]].
== Week 9 ==
=== Tuesday (Mar 17) ===
* Upstreaming
** Git Discussion
** Creating a Patch
** Various open source community workflows
=== Thursday (Mar 19) ===
* Spinlocks
** The need for Atomics in Spinlocks
** Using Intrinsics for Atomic Operations
* Tail Call Optimization (TCO)
** gcc will perform TCO at -O2 and higher
** Important to ensure that gcc recognizes code patterns that permit TCO to be applied
=== Week 9 Deliverables ===
* Blog at least once (and ideally more than once) about your Project
** Frequent shorter posts are better than rare long ones
** Aim to make steady progress on your project, a bit each day
** Blog about your evolving project plan and the steps you're making along the way
** Keep the work short, and focus on narrowing the scope of work as early as possible
** Keep talking to the community
== Week 10 ==
=== Tuesday (Mar 24) ===
* Discussion of GCC Intrinsics
** Where to find documentation: [https://gcc.gnu.org/onlinedocs/ GCC Manual]
** __atomic vs __sync intrinsic families
* Examination of Build Files
** Differential analysis of successful and unsuccessfull build
=== Thursday (Mar 26) ===
* Project Presentations - Stage 2
** At this point, you should have a proposed patch that you're working to get upstream
=== Week 10 Deliverables ===
* Blog posts about your project
** Include information about your patch(es)
** Include links to discussion about the patch(es) with the community (e.g., link to bug/issue tracker entries or email archives)
** If you don't have patches and/or have not pushed them upstream yet, describe the state of your project and your plan to get changes upstream.
* Blogs will be marked Monday for Stage 2 project work (20%)
== Week 11 ==
=== Tuesday (Mar 31) ===
Your professor will be away. You are welcome to use the classroom for a project hacking time and collaboration with your colleagues.
=== Thursday (Apr 2) ===
* Single Instruction / Multiple Data (SIMD)
** Brief look at x86_64 & AArch64 implementations of SIMD
=== Week 11 Deliverables ===
* Blog about your ongoing project work. Please post at least 1-2 entries per week.
== Week 12 ==
=== Tuesday (Apr 7) ===
* Discussion & Hacking Session
=== Thursday (Apr 9) ===
* Vectorization
** Using Intrinsics
** Using Auto-Vectorization
=== Week 12 Deliverables ===
* Blog about your ongoing project work. Please post at least 1-2 entries per week.
* You should have patches (code, makefiles, documentation, or tests) in the upstream review process at or before this point.
* Blog about vectorization - specifically:
** What -O level and/or options are needed to turn on the auto-vectorizer in GCC
** At least three limitations -- conditions under which the vectorization will not be performed
** The significance of alignment and non-overlapping pointers for vectorization
== Week 13 ==
=== Tuesday (Apr 14) ===
* Informal Project Presentations - Phase 3
=== Thursday (Apr 16) ===
* Wrap-up Session
=== Week 13 Deliverables ===
* Blog about your ongoing project work. Your patches should be through the upstream review process.
* Final date for posting about your project: April 22.
<!--
== Misc / Relocated ==
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
* [[Winter 2015 SPO600 Assembly Language Presentation|Select and prepare to teach the class about a specific small topic related to assembly language / machine language programming]].
== Week 3 ==
This week [[User:Chris Tyler|your professor]] is at [https://www.linaro.org/connect/lcu/lcu14/ Linaro Connect], an engineering conference run by [http://www.linaro.org Linaro] - a distributed not-for-profit collaborative technology company focused on Linux on ARM. You can [https://www.linaro.org/connect/lcu/lcu14/remote/ participate remotely] and may find some of the sessions interesting.
* [[Fall 2014 SPO600 Assembly Language Presentation|Select and prepare to teach the class about a specific small topic related to assembly language / machine language programming]].
=== Week 3 Deliverables ===
* Be prepared to give your [[Fall 2014 SPO600 Assembly Language Presentation|presentation]] on Tuesday of next week (September 23).
== Week 4 ==
=== Tuesday (Sep 23) ===
* Give your [[Fall 2014 SPO600 Assembly Language Presentation|presentation about an assembly language topic]] - teach your SPO600 colleagues
=== Friday (Sep 26) ===
* Remainder of the [[Fall 2014 SPO600 Assembly Language Presentation|presentations about an assembly language topic]]
* [[Assembler Basics|Introduction to assembly language]]
* Writing x86_64 and aarch64 code in the [[SPO600 Assembler Lab|Assembly language lab (Lab 3)]]
=== Week 4 Deliverables ===
* Blog your [[Fall 2014 SPO600 Assembly Language Presentation|presentation]]
== Week 5 ==
=== Tuesday (Sep 30) ===
* [[SPO600 Assembler Lab|Assembler Lab]]
=== Friday (Oct 3) ===
* [[Inline Assembly Language]]
* [[Compiler Optimizations]]
The [http://performance.linaro.org/ Linaro Performance Challenge] is a project initiated by [http://en.wikipedia.org/wiki/Jon_Hall_%28programmer%29 Jon "Maddog" Hall] and [http://www.linaro.org Linaro] to port or make portable open source software packages which contain platform-specific code and which may not build on the new Aarch64 architecture.
(There are two videos about the challenge, both of which are from late 2013 while the program was being finalized: [https://www.youtube.com/watch?v=Lo1dBB3tke8 One of an interview with Maddog and Steve Macintyre], and [http://people.linaro.org/linaro-connect/lcu13/videos/10-28-Monday/LCU13%20ARM%20Performance%20Optimizations.mp4 the other of a Linaro Connect presentation by Maddog]).
The [http://performance.linaro.org/find/ list of packages] for this project was originally developed by the UK Debian developer Steve Macintyre, who works for Linaro. His focus in developing that list was to find packages that contained assembly language code for x86 (or other platforms) and which did not have assembly language code for ARM, especially Aarch64. As a result, the list includes many false-positives: there are many packages on there that can successfully build on ARM, either due to C work-arounds for the missing assembly code, or conditional compilation of the assembly code, or recent updates to the software, or other reasons.
In this class, we're going to start to triage this list by analyzing which packages exist in the Fedora package set and which have been successfully built for the aarch64 architecture.
The list has been processed with these steps:
# Grab the list of packages from the Linaro Performance Challenge site.
# Find out the corresponding names of the packages in the Fedora package set. Most of these will be the same as in the list, but some may be different.
# Find out which packages have not been built for Fedora on aarch64
# Divide the resulting list up between the members of the class for further analysis
'''Please see the [[Fall 2014 SPO600 Packages by Participant]] and perform the steps listed there.'''
{{Admon/tip|Participating in the Linaro Performance Challenge|You are invited to participate in the [http://performance.linaro.org Linaro Performance Challenge] directly, utilizing the work you are doing in the SPO600 course. Doing so may enable you to receive a prize for participation and the chance to win a trip to a Linaro Connect conference. In order to participate in the Challenge, you will need to comply with the technical requirements and rules of the Challenge.<br/><br/>Your participation in this course, and the mark you receive in this course, are independent of your participation in the Linaro Performance Challenge.<br/><br/>In other words: Linaro and Seneca are distinct entities, and although you can participate in both the Challenge and SPO600 with the same project, Seneca assumes no responsibility for your interaction with Linaro, and vice-versa.}}
=== Week 5 Deliverables ===
* Blog about the [[SPO600 Assembler Lab|assembler lab (Lab 3)]].
* Do the tasks assigned on the [[Fall 2014 SPO600 Packages by Participant]] page, and blog about it.
== Week 6 ==
=== Tuesday (Oct 7) ===
Jon "Maddog" Hall will be joining us for a remote talk and Q&A via Google Hangout.
=== Friday (Oct 10) ===
In groups, we'll be analyzing software pacakges from the [[Fall 2014 SPO600 Packages by Participant|Packages by Participant]] list to find the platform-specific code and build instructions.
=== Week 6 Deliverables ===
* Pick three additional packages (not the ones done in class) from your section of the [[Fall 2014 SPO600 Packages by Participant|Packages by Participant]] list and find the platform-specific code (or build instructions). Figure out what that code does, and document that on the list page. Blog about your results and your reflections on the task.
== Week 7 ==
=== Tuesday (Oct 14) ===
Discussion of some of the reasons that platform specific (usually assembly language) code is used in software
==== Memory Barriers ====
'''Memory Barriers''' ensure that memory accesses are sequenced so that multiple threads, processes, cores, or IO devices see a predictable view of memory.
* Leif Lindholm provides an excellent explanation of memory barriers.
** Blog series - I recommend this series, especially the introduction, as a very clear explanation of memory barrier issues.
*** Part 1 - [http://community.arm.com/groups/processors/blog/2011/03/22/memory-access-ordering--an-introduction Memory Access Ordering - An Introduction]
*** Part 2 - [http://community.arm.com/groups/processors/blog/2011/04/11/memory-access-ordering-part-2--barriers-and-the-linux-kernel Memory Access Ordering Part 2 - Barriers and the Linux Kernel]
*** Part 3 - [http://community.arm.com/groups/processors/blog/2011/10/19/memory-access-ordering-part-3--memory-access-ordering-in-the-arm-architecture Memory Access Ordering Part 3 - Memory Access Ordering in the ARM Architecture]
** Presentation at Embedded Linux Conference 2010 (Note: Acquire/Release in C++11 and ARMv8 aarch64 appeared after this presentation):
*** [http://elinux.org/images/f/fa/Software_implications_memory_systems.pdf Slides]
*** [http://free-electrons.com/pub/video/2010/elce/elce2010-lindholm-memory-450p.webm Video]
* [http://www.rdrop.com/users/paulmck/scalability/paper/whymb.2010.07.23a.pdf Memory Barriers - A Hardware View for Software Hackers] - This is a highly-rated paper that explains memory barrier issues - as the title suggests, it is designed to describe the hardware origin of the problem to software developers. Despite the fact that it is an introduction to the topic, it is still very technical.
* [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka14041.html ARM Technical Support Knowlege Article - In what situations might I need to insert memory barrier instructions?] - Note that there are some additional mechanisms present in ARMv8 aarch64, including Acquire/Release.
* [https://www.kernel.org/doc/Documentation/memory-barriers.txt Kernel Documentation on Memory Barriers] - discusses the memory barrier issue generally, and the solutions used within the Linux kernel. This is part of the kernel documentation.
* Acquire-Release mechanisms
** [http://blogs.msdn.com/b/oldnewthing/archive/2008/10/03/8969397.aspx MSDN Blog Post] with a very clear explanation of Acquire-Release.
** [http://preshing.com/20130922/acquire-and-release-fences/ Preshing on Programming post] with a good explanation.
** [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.genc010197a/index.html ARMv8 Instruction Set Architecture Manual] (ARM InfoCentre registration required) - See the section on Acquire/Release and Load/Store, especially Load/Store Exclusive (e.g., LDREX)
==== Atomics ====
'''Atomics''' are operations which must be completed in a single step (or appear to be completed in a single step) without potential interruption.
* Wikipedia has a good basic overview of the need for atomicity in the article on [http://en.wikipedia.org/wiki/Linearizability Linerarizability]
=== Friday (Oct 17) ===
* [[Compiler Intrinsics]]
** The use of compiler intrinsics (e.g., those in gcc, or in another compiler) locks you into the use of that specific compiler (or another that supports the exact same intrinsics), but it provides platform portability. It is better to use language features (e.g., C11 or C++11 atomic and acquire/release syntax) where possible, but since that is often not possible, the use of compiler intrinsics is more maintainable than inline assembly.
** GCC provides intrinsics (built-in functions) for atomic operations, as documented in the GCC manual:
*** [http://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fsync-Builtins.html#_005f_005fsync-Builtins Legacy __sync Built-in Functions for Atomic Memory Access]
*** [http://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fatomic-Builtins.html#_005f_005fatomic-Builtins Built-in functions for memory model aware atomic operations]
** The Fedora project has some guidelines/recommendations for the use of these GCC builtins:
*** http://fedoraproject.org/wiki/Architectures/ARM/GCCBuiltInAtomicOperations
* Select your project(s):
** Criteria:
**# Interest
**# Scope
**# Fit between your skills and project needs
**# Upstream status (e.g., dead project)
=== Week 7 Deliverables ===
# Select at least two software packages from the [http://performance.linaro.org Linaro performance web site] and/or the [[Fall 2014 SPO600 Packages by Participant|Packages]] page.
# Record your choice on:
## The [[Fall 2014 SPO600 Participants|Participants page]] - so that your colleagues in class know that you're working on the package(s). '''Note:''' Package choices will be approved by [[User:Chris Tyler|your professor]], but will usually be accepted on a first-come, first-served basis.
## The [http://performance.linaro.org Linaro performance web site] - this will tell other people outside of our group within the Linux-on-ARM community that you are working on the package(s).
# Investigate and blog about your choice.
'''Over reading week:'''
# Contact the upstream communities for the packages you have selected -- so that they know that you are working on the package and to open a channel of communication for your forthcoming patches (or benchmarks, or other results).
# Formulate a work plan that will conclude with landing your software changes in the upstream software before the end of the course.
# Blog about your work plan and what you need to investigate/learn in order to complete your project.
== Week 8 ==
=== Tuesday (Oct 28) ===
Working with the Code
* Working with GIT
* Working with other version control systems
Looking at How Distributions Package the Code
* Using fedpkg
=== Friday (Oct 31) ===
* Benchmarking and Profiling
* Profiling with <code>gprof</code>
** Build with profiling enabled (use the option <code>-pg</code> with both gcc and ld)
** Run the profile-enabled executable
** Analyze the data in the <code>gmon.out</code> file
*** <code>gprof ''nameOfBinary''</code> # Displays text profile including call graph
*** <code>gprof ''nameOfBinary'' | gprof2dot | dot | display -</code> # Displays visualization of call graph
Resources
* [https://sourceware.org/binutils/docs-2.16/gprof/ GProf Manual]
* [http://www.thegeekstuff.com/2012/08/gprof-tutorial/ Profiling with GProf]
=== Week 8 Deliverables ===
* Blog about your progress connecting with the communities associated with your projects and working with the code.
== Week 9 ==
=== Tuesday (Nov 4) ==
* Profiling/baseline benchmarking review
* Hacking session
=== Friday (Nov 7) ===
* Hacking session
=== Week 9 Deliverables ===
* Blog about your baseline benchmarking/profiling.
== Week 10 ==
=== Tuesday (Nov 11) ===
* Presentation on your project status
=== Friday (Nov 14) ===
* Running AArch64 code on x86
** Foundation models
** [[AArch64 QEMU User Space Emulation]]
=== Week 10 Deliverables ===
* Blog about your project status
== Week 11 ==
=== Tuesday (Nov 18) ===
* Discussion and hack session
** Blog post about upstreaming: [https://www.linaro.org/blog/core-dump/working-upstream/ What do we mean by working upstream: A long-term contributor's view]
=== Friday (Nov 21) ===
* Discussion and hack session
=== Week 11 Deliverables ===
* Upstream your changes/test results/documentation
* Blog about your work
* '''Note: Blogs will be marked as of Nov 21 11:59 pm'''
== Week 12 ==
=== Tuesday (Nov 25) ===
* Project update presentations
=== Friday (Nov 28) ===
* Discussion and hack session: ''Commercial vs. Technical Reality''
== Week 13 ==
=== Tuesday (Dec 2) ===
* Discussion and hack session
=== Friday (Dec 5) ===
* Wrap-up session
* '''Remember: Final project submissions via blog are due 11:59 pm December 10.'''
-->
<BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/><BR/>
{{Admon/important|It's Alive!|This [[SPO600]] weekly schedule will be updated as the course proceeds - dates and content are subject to change. The cells in the summary table will be linked to relevant resources and labs as the course progresses.}}
For the Winter 2015 version of the weekly schedule, see [[Winter 2015 SPO600 Weekly Schedule]].
== Schedule Summary Table ==
This is a summary/index table. Please follow the links in each cell for additional detail -- especially for the ''Deliverables'' column.
{|cellspacing="0" width="100%" cellpadding="5" border="1" style="background: #e0e0ff"
|-
!Week!!Week of...!!Tuesday!!Thursday!!Deliverables<br/>(Summary - click for details)
|-
|1||Jan 12||[[#Tuesday (Jan 13)|Introduction to Software Porting, Portability, Benchmarking, and Optimization / How is code accepted into an open source project? (Lab 1)]]||[[#Thursday (Jan 15)|Benchmarking and Profiling]]||[[#Week 1 Deliverables|Set up accounts, and blog a comparision of code reviews in two communities (Lab 1).]]
|-
|2||Jan 19||[[#Tuesday (Jan 20)|Working with the code / Building]]||[[#Thursday (Jan 22)|Build and benchmark a portion of the LAMP stack (Lab 2)]]||[[#Week 2 Deliverables|Blog about your baseline data (Lab 2)]]
|-
|3||Jan 26||[[#Tuesday (Jan 27)|Profiling: Finding the pain points (Lab 3)]]||[[#Thursday (Jan 29)|Computer architecture overview]]||[[#Week 3 Deliverables|Blog about the profiling results and pain points discovered (Lab 3)]]
|-
|4||Feb 2||[[#Tuesday (Feb 3)|Compiled C Lab (Lab 4)]]||[[#Thursday (Feb 5)|Compiler optimizations]]||[[#Week 4 Deliverables|Blog a commentary on the Compiled C Lab (Lab 4).]]
|-
|5||Feb 9||colspan="2" align="center"|Linaro Connect - No classes scheduled<br />[[#Week 5|'''Prepare a presentation on a selected topic about platform-specific code.''']]||[[#Week 5 Deliverables|Be prepared to present your topic.]]
|-
|6||Feb 16||[[#Tuesday (Feb 17)|Presentations on platform-specific code.]]||[[#Thursday (Feb 19)|Presentations on platform-specific code.]]||[[#Week 6 Deliverables|Blog about your presentation.]]
|-
|7||Feb 23||[[#Tuesday (Feb 24)|Assembly lab (Lab 5)]]||[[#Thursday (Feb 26)|Inline assembly lab and Course Projects]]||[[#Week 7 Deliverables|Blog about the Assembly Lab (Lab 5) and start project investigation.]]
|-style="background: #f0f0ff"
|Study Week||Mar 2||colspan="3" align="center"|Study Week - No classes! Please work on your initial project investigation.
|-
|8||Mar 9||[[#Tuesday (Mar 10)|Project discussion, and Reading Reference Documentation.]]||[[#Thursday (Mar 12)|Project presentations - Stage 1]]||[[#Week 8 Deliverables|Blog about your project progress - this will be used to assign your 1st Project marks.]]
|-
|9||Mar 16||[[#Tuesday (Mar 17)|Upstreaming]]||[[#Thursday (Mar 19)|Spinlocks and Tail Call Optimization]]||[[#Week 9 Deliverables|Blog about your project work.]]
|-
|10||Mar 23||[[#Tuesday (Mar 24)|Portable alternatives to Assembler]]||[[#Thursday (Mar 26)|Project Presentations - Stage 2]]||[[#Week 10 Deliverables|Blog about your project progress - this will be used to assign your 2nd Project Marks.]]
|-
|11||Mar 30||[[#Tuesday (Mar 31)|Hack Session]] (Professor will not be present)||[[#Thursday (Apr 2)|SIMD]]||[[#Week 11 Deliverables|Blog about SIMD/vectorization and your project.]]
|-
|12||Apr 6||[[#Tuesday (Apr 7)|Discussion & Hack Session]]||[[#Thursday (Apr 9)|Vectorization]]||[[#Week 12 Deliverables|Blog about your work.]]
|-
|13||Apr 13||[[#Tuesday (Apr 14)|Project Presentations - Stage 3]]||[[#Thursday (Apr 16)|Wrap-up Session]]||[[#Week 13 Deliverables|Blog about your project progress - this will be used to assign your 3rd project marks.]]
|-
|-style="background: #f0f0ff"
|Exam Week||Apr 20||colspan="3" align="center"|Exam Week - No exam in this course!
|}
== Evaluation ==
{|cellspacing="0" width="100%" cellpadding="5" border="1" style="background: #e0ffe0"
!Category!!Percentage!!Evaluation Dates
|-
|Communication||align="right"|20%||January 31, February 28, March 27, April 22
|-
|Quizzes||align="right"|10%||May be held during any class, usually at the start of class. A minimum of 5 one-page quizzes will be given. No make-up/retake option is offered if you miss a quiz. Lowest 3 scores will not be counted.
|-
|Labs||align="right"|10%||See deliverables column above.
|-
|Project work||align="right"|60%||March 16 (15%), March 31 (20%), April 22 (25%)
|}
== Week 1 ==
=== Tuesday (Jan 13) ===
==== Introduction to the Problems ====
===== Porting and Portability =====
* Most software is written in a '''high-level language''' which can be compiled into [[Machine Language|machine code]] for a specific computer architecture. In many cases, this code can be compiled for multiple architectures. However, there is a lot of existing code that contains some architecture-specific code fragments written in [[Assembly Language]] (or, in some cases, machine-specific high-level code).
* Reasons for writing code in Assembly Langauge include:
** Performance
** [[Atomic Operation|Atomic Operations]]
** Direct access to hardware features, e.g., CPUID registers
* Most of the historical reasons for including assembler are no longer valid. Modern compilers can out-perform most hand-optimized assembly code, atomic operations can be handled by libraries or [[Compiler Intrinsics|compiler intrinsics]], and most hardware access should be performed through the operating system or appropriate libraries.
* A new architecture has appeared: Aarch64, which is part of [http://www.arm.com/products/processors/instruction-set-architectures/armv8-architecture.php ARMv8]. This is the first new [[Computer Architecture|computer architecture]] to appear in several years (at least, the first mainstream computer architecture).
* At this point, most key open source software (the software typically present in a Linux distribution such as Ubuntu or Fedora, for example) now runs on AArch64. However, it may not run as well as on older architectures (such as x86_64).
===== Benchmarking and Profiling =====
Benchmarking involves testing software performance under controlled conditions so that the performance can be compared to other software, the same software operating on other types of computers, or so that the impact of a change to the software can be gauged.
Profiling is the process of analyzing software performance on finer scale, determining resource usage per program part (typically per function/method). This can identify software bottlenecks and potential targets for optimization.
===== Optimization =====
Optimization is the process of evaluating different ways that software can be written or built and selecting the option that has the best performance tradeoffs.
Optimization may involve substituting software algorithms, altering the sequence of operations, using architecture-specific code, or altering the build process. It is important to ensure that the optimized software produces correct results and does not cause an unacceptable performance regression for other use-cases, system configurations, operating systems, or architectures.
The definition of "performance" varies according to the target system and the operating goals. For example, in some contexts, low memory or storage usage is important; in other cases, fast operation; and in other cases, low CPU utilization or long battery life may be the most important factor. It is often possible to trade off performance in one area for another; using a lookup table, for example, can reduce CPU utilization and improve battery life in some algorithms, in return for increased memory consumption.
Most advanced compilers perform some level of optimization, and the options selected for compilation can have a significant effect on the trade-offs made by the compiler, affecting memory usage, execution speed, executable size, power consumption, and debuggability.
===== Build Process =====
Building software is a complex task that many developers gloss over. The simple act of compiling a program invokes a process with five or more stages, including pre-proccessing, compiling, optimizing, assembling, and linking. However, a complex software system will have hundreds or even thousands of source files, as well as dozens or hundreds of build configuration options, auto configuration scripts (cmake, autotools), build scripts (such as Makefiles) to coordinate the process, test suites, and more.
The build process varies significantly between software packages. Most software distribution projects (including Linux distributions such as Ubuntu and Fedora) use a packaging system that further wraps the build process in a standardized script format, so that different software packages can be built using a consistent process.
In order to get consistent and comparable benchmark results, you need to ensure that the software is being built in a consistent way. Altering the build process is one way of optimizing software.
Note that the build time for a complex package can range up to hours or even days!
==== Course Projects ====
In this course, you will:
# Test the performance of all or part of the LAMP stack.
# Determine how the performance of one specific part of the stack could be improved, either specifically on AArch64 systems (without detriment to other systems) or on all systems.
# Prepare a fix/patch for the software to implement that performance improvement.
# Prove that your changes do not cause any unacceptable performance regressions (Note: there might be performance regressions which are considered acceptable!).
# Upstream your Code - Submit your code to the upstream (originating) software project so that it can be incorporated into future versions of the software. This will involve going through a code review to ensure that your code is compatible with and acceptable to the upstream community.
==== General Course Information ====
* Course resources are linked from the CDOT wiki, starting at http://zenit.senecac.on.ca/wiki/index.php/SPO600 (Quick find: This page will usually be Google's top result for a search on "SPO600").
* Coursework is submitted by blogging.
* Quizzes will be short (1 page) and will be held without announcement at any time. Your lowest three quiz scores will not be counted, so do not worry if you miss one or two.
* Course marks (see Weekly Schedule for dates):
** 60% - Project Deliverables
** 20% - Communication (Blog and Wiki writing)
** 20% - Labs and Quizzes (10% labs - completed/not completed; 10% for quizzes - lowest 3 scores not counted)
* All classes will be held in an [[Active Learning Classroom]] -- you are encouraged to bring your own laptop to class. If you do not have a laptop, consider signing one out of the Learning Commons for class, or using a smartphone with an HDMI adapter.
* For more course information, refer to the SPO600 Weekly Schedule (this page), the [http://www.senecacollege.ca/ssos/findWithoutSemester/spo600/sict Course Outline], and [[SPO600 Course Policies]].
<!-- * Introduction to the [http://linaro.org Linaro] Code Porting/Optimization project. -->
<!-- * Optional: You can participate in the [http://linaro.org Linaro] Code Porting/Optimization contest. For details, see the [http://www.youtube.com/watch?v=Lo1dBB3tke8 YouTube video] of Jon "maddog" Hall and Steve Mcintyre at Linaro Connect USA 2013. -->
==== Discussion of how open source communities work ====
* Background for the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
=== Thursday (Jan 15) ===
* Benchmarking
* Profiling
=== Week 1 Deliverables ===
# Set up your [[SPO600 Communication Tools]] - in particular, set up a blog and add it to [http://zenit.senecac.on.ca/~chris.tyler/planet/ Planet CDOT] (via the [[Planet CDOT Feed List]]).
# Add yourself to the [[Winter 2015 SPO600 Participants]] page (leave the projects columns blank).
# Generate a [[SSH#Using_Public_Keys_with_SSH|pair of keys]] for [[SSH]] and email the public key to your professor.
# Sign and return the [[Open Source Professional Option Student Agreement]].
# Optional but recommended: [[SPO600 Host Setup|Set up a personal Fedora system]].
== Week 2 ==
=== Tuesday (Jan 20) ===
{{Admon/tip|Bring Your Laptop|Classes are held in a [[Active Learning Classroom]]. If you have a laptop or other device with a VGA or HDMI output (such as a smartphone!) please bring it. You'll need either a local linux environment or an [[SSH]] client -- which is built-in to Linux, Mac, and Chromebook systems, and readily available for Windows, Android, and iOS devices.}}
Status Check
* Introductions around the Room
** Name
** Program
** Interest in the course
** Results of <code>gzip</code> benchmarking and most interesting thing you observed
* Check the [[SPO600 Servers|server accounts]] that were set up with your [[SSH]] keys
* Sheets from Last Week
** Open Source Student Agreement
** Survey (Optional)
Working with the Code
* Getting Code
** In a tarball
** From git
*** Git basics
** Working with other version control systems
* Building the Code
** Make
** Configuration tools (autotools, cmake)
** The compiler toolchain
*** Preprocessor
*** Compiler
*** Assembler
*** Linker
** Debug vs. Non-debug/Stripped binaries
Looking at How Distributions Package the Code
* Using fedpkg
==== Resources ====
* [https://sourceware.org/binutils/docs-2.16/gprof/ GProf Manual]
* [http://www.thegeekstuff.com/2012/08/gprof-tutorial/ Profiling with GProf]
=== Thursday (Jan 22) ===
* [[SPO600 Baseline Builds and Benchmarking Lab|Baseline Builds and Benchmarking Lab (Lab 2)]]
=== Week 2 Deliverables ===
* Complete and blog your conclusion to the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
* Blog your baseline data from the [[SPO600 Baseline Builds and Benchmarking Lab|Baseline Builds and Benchmarking lab (Lab 2)]].
== Week 3 ==
=== Tuesday (Jan 27) ===
Profiling
* Profiling with <code>gprof</code>
** Build with profiling enabled (use the option <code>-pg</code> with both gcc and ld)
** Run the profile-enabled executable
** Analyze the data in the <code>gmon.out</code> file
*** <code>gprof ''nameOfBinary''</code> # Displays text profile including call graph
*** <code>gprof ''nameOfBinary'' | gprof2dot | dot | display -</code> # Displays visualization of call graph
* Other profiling tools
** OProf, SystemTap, and others
* [[SPO600 Profiling Lab]] (Lab 3)
=== Thursday (Jan 29) ===
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
=== Week 3 Deliverables ===
* Complete and blog your conclusions to the [[SPO600 Profiling Lab|Profiling Lab (Lab 3)]].
== Week 4 ==
=== Tuesday (Feb 3) ===
* [[SPO600 Compiled C Lab|Compiled C Lab (Lab 4)]]
=== Thursday (Feb 5) ===
* [[Compiler Optimizations]]
=== Week 4 Deliverables ===
* Blog your [[SPO600 Compiled C Lab|Compiled C Lab (Lab 4)]] results. Be sure to include a reflective section on what you learned.
* Select your topic for the [[Winter 2015 SPO600 Platform Specific Code Presentation|Platform-Specific Code Presentation]].
== Week 5 ==
* Prepare your [[Winter 2015 SPO600 Platform Specific Code Presentation|Platform-Specific Code Presentation]].
=== Week 5 Deliverables ===
* Be ready to [[Winter 2015 SPO600 Platform Specific Code Presentation|present]].
== Week 6 ==
=== Tuesday (Feb 17) ===
* Introduction to the [http://www.96boards.org/products/hikey/ HiKey] board and the [http://www.96boards.org/ 96Boards] project.
* [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
=== Thursday (Feb 19) ===
* [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
=== Week 6 Deliverables ===
* Blog about your presentation.
== Week 7 ==
=== Tuesday (Feb 24) ===
* [[SPO600 Assembler Lab|Assembly language lab (Lab 5)]]
=== Thursday (Feb 26) ===
* Remaining [[Winter 2015 SPO600 Platform Specific Code Presentation|Presentations on platform-specific code]]
* [[Inline Assembly Language]]
* [[Winter 2015 SPO600 Project|Course Projects]]
=== Week 7 Deliverables ===
* Blog your conclusion to the [[SPO600 Assembler Lab|assembly language lab (Lab 5)]] - See the ''Deliverables'' section in the lab instructions for details on what to include in your blog post.
== Week 8 ==
=== Tuesday (Mar 10) ===
* Project discussion
** Discussion of project ideas and fine-tuning of project plans
** Next steps
** Addressing Problem Areas
* Accessing and Reading Reference Documentation
** AArch64 ISA
=== Thursday (Mar 12) ===
* Project presentations
** Provide a very short (2 minute) overview of your project. Include:
*** Which piece of software you are working on
*** What area of that software needs optimization/performance tuning
*** How you are going to perform the optimization/tuning (algorithm replacement, platform-specific code, removing platform-specific code, build options, and so forth)
*** Plans for the next step
*** Engagement with the upstream community
* Use this project presentation to tell the class what you're working on and incorporate feedback into your blog post
=== Week 8 Deliverables ===
* Blog about your project and plans, incorporating feedback from your presentation
* Add your project to the [[Winter 2015 SPO600 Participants|Participants and Project Table]].
== Week 9 ==
=== Tuesday (Mar 17) ===
* Upstreaming
** Git Discussion
** Creating a Patch
** Various open source community workflows
=== Thursday (Mar 19) ===
* Spinlocks
** The need for Atomics in Spinlocks
** Using Intrinsics for Atomic Operations
* Tail Call Optimization (TCO)
** gcc will perform TCO at -O2 and higher
** Important to ensure that gcc recognizes code patterns that permit TCO to be applied
=== Week 9 Deliverables ===
* Blog at least once (and ideally more than once) about your Project
** Frequent shorter posts are better than rare long ones
** Aim to make steady progress on your project, a bit each day
** Blog about your evolving project plan and the steps you're making along the way
** Keep the work short, and focus on narrowing the scope of work as early as possible
** Keep talking to the community
== Week 10 ==
=== Tuesday (Mar 24) ===
* Discussion of GCC Intrinsics
** Where to find documentation: [https://gcc.gnu.org/onlinedocs/ GCC Manual]
** __atomic vs __sync intrinsic families
* Examination of Build Files
** Differential analysis of successful and unsuccessfull build
=== Thursday (Mar 26) ===
* Project Presentations - Stage 2
** At this point, you should have a proposed patch that you're working to get upstream
=== Week 10 Deliverables ===
* Blog posts about your project
** Include information about your patch(es)
** Include links to discussion about the patch(es) with the community (e.g., link to bug/issue tracker entries or email archives)
** If you don't have patches and/or have not pushed them upstream yet, describe the state of your project and your plan to get changes upstream.
* Blogs will be marked Monday for Stage 2 project work (20%)
== Week 11 ==
=== Tuesday (Mar 31) ===
Your professor will be away. You are welcome to use the classroom for a project hacking time and collaboration with your colleagues.
=== Thursday (Apr 2) ===
* Single Instruction / Multiple Data (SIMD)
** Brief look at x86_64 & AArch64 implementations of SIMD
=== Week 11 Deliverables ===
* Blog about your ongoing project work. Please post at least 1-2 entries per week.
== Week 12 ==
=== Tuesday (Apr 7) ===
* Discussion & Hacking Session
=== Thursday (Apr 9) ===
* Vectorization
** Using Intrinsics
** Using Auto-Vectorization
=== Week 12 Deliverables ===
* Blog about your ongoing project work. Please post at least 1-2 entries per week.
* You should have patches (code, makefiles, documentation, or tests) in the upstream review process at or before this point.
* Blog about vectorization - specifically:
** What -O level and/or options are needed to turn on the auto-vectorizer in GCC
** At least three limitations -- conditions under which the vectorization will not be performed
** The significance of alignment and non-overlapping pointers for vectorization
== Week 13 ==
=== Tuesday (Apr 14) ===
* Informal Project Presentations - Phase 3
=== Thursday (Apr 16) ===
* Wrap-up Session
=== Week 13 Deliverables ===
* Blog about your ongoing project work. Your patches should be through the upstream review process.
* Final date for posting about your project: April 22.
<!--
== Misc / Relocated ==
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
* [[Winter 2015 SPO600 Assembly Language Presentation|Select and prepare to teach the class about a specific small topic related to assembly language / machine language programming]].
== Week 3 ==
This week [[User:Chris Tyler|your professor]] is at [https://www.linaro.org/connect/lcu/lcu14/ Linaro Connect], an engineering conference run by [http://www.linaro.org Linaro] - a distributed not-for-profit collaborative technology company focused on Linux on ARM. You can [https://www.linaro.org/connect/lcu/lcu14/remote/ participate remotely] and may find some of the sessions interesting.
* [[Fall 2014 SPO600 Assembly Language Presentation|Select and prepare to teach the class about a specific small topic related to assembly language / machine language programming]].
=== Week 3 Deliverables ===
* Be prepared to give your [[Fall 2014 SPO600 Assembly Language Presentation|presentation]] on Tuesday of next week (September 23).
== Week 4 ==
=== Tuesday (Sep 23) ===
* Give your [[Fall 2014 SPO600 Assembly Language Presentation|presentation about an assembly language topic]] - teach your SPO600 colleagues
=== Friday (Sep 26) ===
* Remainder of the [[Fall 2014 SPO600 Assembly Language Presentation|presentations about an assembly language topic]]
* [[Assembler Basics|Introduction to assembly language]]
* Writing x86_64 and aarch64 code in the [[SPO600 Assembler Lab|Assembly language lab (Lab 3)]]
=== Week 4 Deliverables ===
* Blog your [[Fall 2014 SPO600 Assembly Language Presentation|presentation]]
== Week 5 ==
=== Tuesday (Sep 30) ===
* [[SPO600 Assembler Lab|Assembler Lab]]
=== Friday (Oct 3) ===
* [[Inline Assembly Language]]
* [[Compiler Optimizations]]
The [http://performance.linaro.org/ Linaro Performance Challenge] is a project initiated by [http://en.wikipedia.org/wiki/Jon_Hall_%28programmer%29 Jon "Maddog" Hall] and [http://www.linaro.org Linaro] to port or make portable open source software packages which contain platform-specific code and which may not build on the new Aarch64 architecture.
(There are two videos about the challenge, both of which are from late 2013 while the program was being finalized: [https://www.youtube.com/watch?v=Lo1dBB3tke8 One of an interview with Maddog and Steve Macintyre], and [http://people.linaro.org/linaro-connect/lcu13/videos/10-28-Monday/LCU13%20ARM%20Performance%20Optimizations.mp4 the other of a Linaro Connect presentation by Maddog]).
The [http://performance.linaro.org/find/ list of packages] for this project was originally developed by the UK Debian developer Steve Macintyre, who works for Linaro. His focus in developing that list was to find packages that contained assembly language code for x86 (or other platforms) and which did not have assembly language code for ARM, especially Aarch64. As a result, the list includes many false-positives: there are many packages on there that can successfully build on ARM, either due to C work-arounds for the missing assembly code, or conditional compilation of the assembly code, or recent updates to the software, or other reasons.
In this class, we're going to start to triage this list by analyzing which packages exist in the Fedora package set and which have been successfully built for the aarch64 architecture.
The list has been processed with these steps:
# Grab the list of packages from the Linaro Performance Challenge site.
# Find out the corresponding names of the packages in the Fedora package set. Most of these will be the same as in the list, but some may be different.
# Find out which packages have not been built for Fedora on aarch64
# Divide the resulting list up between the members of the class for further analysis
'''Please see the [[Fall 2014 SPO600 Packages by Participant]] and perform the steps listed there.'''
{{Admon/tip|Participating in the Linaro Performance Challenge|You are invited to participate in the [http://performance.linaro.org Linaro Performance Challenge] directly, utilizing the work you are doing in the SPO600 course. Doing so may enable you to receive a prize for participation and the chance to win a trip to a Linaro Connect conference. In order to participate in the Challenge, you will need to comply with the technical requirements and rules of the Challenge.<br/><br/>Your participation in this course, and the mark you receive in this course, are independent of your participation in the Linaro Performance Challenge.<br/><br/>In other words: Linaro and Seneca are distinct entities, and although you can participate in both the Challenge and SPO600 with the same project, Seneca assumes no responsibility for your interaction with Linaro, and vice-versa.}}
=== Week 5 Deliverables ===
* Blog about the [[SPO600 Assembler Lab|assembler lab (Lab 3)]].
* Do the tasks assigned on the [[Fall 2014 SPO600 Packages by Participant]] page, and blog about it.
== Week 6 ==
=== Tuesday (Oct 7) ===
Jon "Maddog" Hall will be joining us for a remote talk and Q&A via Google Hangout.
=== Friday (Oct 10) ===
In groups, we'll be analyzing software pacakges from the [[Fall 2014 SPO600 Packages by Participant|Packages by Participant]] list to find the platform-specific code and build instructions.
=== Week 6 Deliverables ===
* Pick three additional packages (not the ones done in class) from your section of the [[Fall 2014 SPO600 Packages by Participant|Packages by Participant]] list and find the platform-specific code (or build instructions). Figure out what that code does, and document that on the list page. Blog about your results and your reflections on the task.
== Week 7 ==
=== Tuesday (Oct 14) ===
Discussion of some of the reasons that platform specific (usually assembly language) code is used in software
==== Memory Barriers ====
'''Memory Barriers''' ensure that memory accesses are sequenced so that multiple threads, processes, cores, or IO devices see a predictable view of memory.
* Leif Lindholm provides an excellent explanation of memory barriers.
** Blog series - I recommend this series, especially the introduction, as a very clear explanation of memory barrier issues.
*** Part 1 - [http://community.arm.com/groups/processors/blog/2011/03/22/memory-access-ordering--an-introduction Memory Access Ordering - An Introduction]
*** Part 2 - [http://community.arm.com/groups/processors/blog/2011/04/11/memory-access-ordering-part-2--barriers-and-the-linux-kernel Memory Access Ordering Part 2 - Barriers and the Linux Kernel]
*** Part 3 - [http://community.arm.com/groups/processors/blog/2011/10/19/memory-access-ordering-part-3--memory-access-ordering-in-the-arm-architecture Memory Access Ordering Part 3 - Memory Access Ordering in the ARM Architecture]
** Presentation at Embedded Linux Conference 2010 (Note: Acquire/Release in C++11 and ARMv8 aarch64 appeared after this presentation):
*** [http://elinux.org/images/f/fa/Software_implications_memory_systems.pdf Slides]
*** [http://free-electrons.com/pub/video/2010/elce/elce2010-lindholm-memory-450p.webm Video]
* [http://www.rdrop.com/users/paulmck/scalability/paper/whymb.2010.07.23a.pdf Memory Barriers - A Hardware View for Software Hackers] - This is a highly-rated paper that explains memory barrier issues - as the title suggests, it is designed to describe the hardware origin of the problem to software developers. Despite the fact that it is an introduction to the topic, it is still very technical.
* [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka14041.html ARM Technical Support Knowlege Article - In what situations might I need to insert memory barrier instructions?] - Note that there are some additional mechanisms present in ARMv8 aarch64, including Acquire/Release.
* [https://www.kernel.org/doc/Documentation/memory-barriers.txt Kernel Documentation on Memory Barriers] - discusses the memory barrier issue generally, and the solutions used within the Linux kernel. This is part of the kernel documentation.
* Acquire-Release mechanisms
** [http://blogs.msdn.com/b/oldnewthing/archive/2008/10/03/8969397.aspx MSDN Blog Post] with a very clear explanation of Acquire-Release.
** [http://preshing.com/20130922/acquire-and-release-fences/ Preshing on Programming post] with a good explanation.
** [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.genc010197a/index.html ARMv8 Instruction Set Architecture Manual] (ARM InfoCentre registration required) - See the section on Acquire/Release and Load/Store, especially Load/Store Exclusive (e.g., LDREX)
==== Atomics ====
'''Atomics''' are operations which must be completed in a single step (or appear to be completed in a single step) without potential interruption.
* Wikipedia has a good basic overview of the need for atomicity in the article on [http://en.wikipedia.org/wiki/Linearizability Linerarizability]
=== Friday (Oct 17) ===
* [[Compiler Intrinsics]]
** The use of compiler intrinsics (e.g., those in gcc, or in another compiler) locks you into the use of that specific compiler (or another that supports the exact same intrinsics), but it provides platform portability. It is better to use language features (e.g., C11 or C++11 atomic and acquire/release syntax) where possible, but since that is often not possible, the use of compiler intrinsics is more maintainable than inline assembly.
** GCC provides intrinsics (built-in functions) for atomic operations, as documented in the GCC manual:
*** [http://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fsync-Builtins.html#_005f_005fsync-Builtins Legacy __sync Built-in Functions for Atomic Memory Access]
*** [http://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fatomic-Builtins.html#_005f_005fatomic-Builtins Built-in functions for memory model aware atomic operations]
** The Fedora project has some guidelines/recommendations for the use of these GCC builtins:
*** http://fedoraproject.org/wiki/Architectures/ARM/GCCBuiltInAtomicOperations
* Select your project(s):
** Criteria:
**# Interest
**# Scope
**# Fit between your skills and project needs
**# Upstream status (e.g., dead project)
=== Week 7 Deliverables ===
# Select at least two software packages from the [http://performance.linaro.org Linaro performance web site] and/or the [[Fall 2014 SPO600 Packages by Participant|Packages]] page.
# Record your choice on:
## The [[Fall 2014 SPO600 Participants|Participants page]] - so that your colleagues in class know that you're working on the package(s). '''Note:''' Package choices will be approved by [[User:Chris Tyler|your professor]], but will usually be accepted on a first-come, first-served basis.
## The [http://performance.linaro.org Linaro performance web site] - this will tell other people outside of our group within the Linux-on-ARM community that you are working on the package(s).
# Investigate and blog about your choice.
'''Over reading week:'''
# Contact the upstream communities for the packages you have selected -- so that they know that you are working on the package and to open a channel of communication for your forthcoming patches (or benchmarks, or other results).
# Formulate a work plan that will conclude with landing your software changes in the upstream software before the end of the course.
# Blog about your work plan and what you need to investigate/learn in order to complete your project.
== Week 8 ==
=== Tuesday (Oct 28) ===
Working with the Code
* Working with GIT
* Working with other version control systems
Looking at How Distributions Package the Code
* Using fedpkg
=== Friday (Oct 31) ===
* Benchmarking and Profiling
* Profiling with <code>gprof</code>
** Build with profiling enabled (use the option <code>-pg</code> with both gcc and ld)
** Run the profile-enabled executable
** Analyze the data in the <code>gmon.out</code> file
*** <code>gprof ''nameOfBinary''</code> # Displays text profile including call graph
*** <code>gprof ''nameOfBinary'' | gprof2dot | dot | display -</code> # Displays visualization of call graph
Resources
* [https://sourceware.org/binutils/docs-2.16/gprof/ GProf Manual]
* [http://www.thegeekstuff.com/2012/08/gprof-tutorial/ Profiling with GProf]
=== Week 8 Deliverables ===
* Blog about your progress connecting with the communities associated with your projects and working with the code.
== Week 9 ==
=== Tuesday (Nov 4) ==
* Profiling/baseline benchmarking review
* Hacking session
=== Friday (Nov 7) ===
* Hacking session
=== Week 9 Deliverables ===
* Blog about your baseline benchmarking/profiling.
== Week 10 ==
=== Tuesday (Nov 11) ===
* Presentation on your project status
=== Friday (Nov 14) ===
* Running AArch64 code on x86
** Foundation models
** [[AArch64 QEMU User Space Emulation]]
=== Week 10 Deliverables ===
* Blog about your project status
== Week 11 ==
=== Tuesday (Nov 18) ===
* Discussion and hack session
** Blog post about upstreaming: [https://www.linaro.org/blog/core-dump/working-upstream/ What do we mean by working upstream: A long-term contributor's view]
=== Friday (Nov 21) ===
* Discussion and hack session
=== Week 11 Deliverables ===
* Upstream your changes/test results/documentation
* Blog about your work
* '''Note: Blogs will be marked as of Nov 21 11:59 pm'''
== Week 12 ==
=== Tuesday (Nov 25) ===
* Project update presentations
=== Friday (Nov 28) ===
* Discussion and hack session: ''Commercial vs. Technical Reality''
== Week 13 ==
=== Tuesday (Dec 2) ===
* Discussion and hack session
=== Friday (Dec 5) ===
* Wrap-up session
* '''Remember: Final project submissions via blog are due 11:59 pm December 10.'''
-->
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