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'''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]]
* Selecting * 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
# 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.
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