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Created page with 'Category:Fall 2014 SPO600 {{Admon/caution|Old Content|This content is being updated from the Fall 2014 to the Winter 2015 version of the course.}} {{Chris Tyler Draft}} {{Adm…'
[[Category:Fall 2014 SPO600]]
{{Admon/caution|Old Content|This content is being updated from the Fall 2014 to the Winter 2015 version of the course.}}
{{Chris Tyler Draft}}
{{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.}}
== 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)|Computer Architecture Overview]]||[[#Week 1 Deliverables|Set up accounts, and blog a comparision of code reviews in two communities (Lab 1).]]
|-
|2||Jan 19||[[#Tuesday (Jan 20)|Compiled C Lab (Lab 2)]]||[[#Thursday (Jan 22)|Prepare a presentation on a selected aspect of assembly language]]||[[#Week 2 Deliverables|Blog a commentary on the Compiled C Lab (Lab 2), and be prepared to give your presentation.]]
|-
|3||Jan 26||[[#Tuesday (Jan 27|Assembly language presentations]]||[[#Thursday (Jan 29)|Assembly language presentations]]||[[#Week 3 Deliverables|Blog about your assembly language presentation.]]
|-
|4||Feb 2||[[#Tuesday (Feb 3)|Assembly lab (Lab 3)]]||[[#Thursday (Feb 5)|Inline assembler / Potential project triage - Scan the potential project list to find out about the packages]]||[[#Week 4 Deliverables|Blog post about the assembly lab (Lab 3) and what you found in the potential projects.]]
|-
|5||Feb 9||colspan="2" align="center"|Linaro Connect - No classes scheduled - '''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)|Compiler intrinsics / Find the platform-specific code in 3 packages (Lab 4).]]||[[#Friday (Oct 10)|Group hack session - Picking your packages.]]||[[#Week 6 Deliverables|Blog about the platform-specific code in 3 packages (Lab 4) and the packages you selected.]]
|-
|7||Oct 13||[#Tuesday (Oct 15)|[[#Tuesday (Oct 14)|Benchmarking and Profiling]]||[[#Friday (Oct 17)|Group hack session - baseline builds, benchmarks, and profiling]]||[[#Week 7 Deliverables|Blog about your baseline data.]]
|-style="background: #f0f0ff"
|Study Week||Oct 20||colspan="3" align="center"|Study Week<br />'''[http://fsoss.ca FSOSS 2014] on Thursday-Friday'''
|-
|8||Oct 27||[[#Tuesday (Oct 28)|Working with the Code]]||[[#Friday (Oct 31)|Group hack session - Profiling]]||[[#Week 8 Deliverables|Blog about your progress.]]
|-
|9||Nov 3||[[#Tuesday (Nov 4)|Profiling review]]||[[#Friday (Nov 11)|Group hack session]]||[[#Week 9 Deliverables|Post baseline stats for your software.]]
|-
|10||Nov 10||[[#Tuesday (Nov 11)|Presentations]]||[[#Friday (Nov 14)|AArch64 on x86_64 / Hack session]]||[[#Week 10 Deliverables|Blog about your project status - 1st project marks.]]
|-
|11||Nov 17||[[#Tuesday (Nov 18)|Discussion and hack session]]||[[#Friday (Nov 21)|Discussion and hack session: Commercial vs. Technical Reality]]||[[#Week 11 Deliverables|Upstream your work and blog about it]]
|-
|12||Nov 24||[[#Tuesday (Nov 25)|Project Update Presentations]]||[[#Friday (Nov 28)|Discussion and hack session]]||[[#Week 12 Deliverables|Blog about your project status - 2nd project marks.]]
|-
|13||Dec 1||[[#Tuesday (Dec 2)|Discussion and Hack Session]]||[[#Friday (Dec 5)|Discussion and Hack Session]]||Code accepted upstream. Blog about it!
|-style="background: #f0f0ff"
|Exam Week||Dec 8||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%||<strike>September 30</strike>, <strike>October 31</strike>, November 21, December 10
|-
|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%||<strike>November 11</strike> (15%), November 25 (20%), December 10 (25%)
|}
== Week 1 ==
=== Friday (Sep 5) ===
==== Introduction to the Problem ====
* Most software is written in a '''high-level language''' which can be compiled into [[Machine Language|machine code]] for a specific architecture. 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).
* There are over 1400 software packages/modules present in GNU Linux systems which contain architecture-specific [[Assembly Language|assembly language code]] or have other portability issues. Most of these packages cannot be built on Aarch64 systems without modification.
==== Course Projects ====
In this course, you will:
# Select two software packages from a list compiled by Steve Macintyre of Linaro. Each of the packages on this list contains assembly language code which is platform-specific.
# Prepare a fix/patch for the software so that it will run on 64-bit ARM systems (aarch64). This may be done at either of two levels:
## Port - Add additional assembly language code for aarch64 (basic solution).
## Make Portable - Remove architecture-specific code, replacing it with compiler intrinsics or high-level code so that the software will successfully build on multiple platforms.
# Benchmark - Prove that your changes do not cause a performance regression on existing platforms, and that (ideally) it improves performance.
# Upstream your Code - Submitting 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)]] which is homework due Week 2).
=== 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 [[Fall 2014 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]].
# [[SPO600 Host Setup|Set up a Fedora 20 system]].
== Week 2 ==
=== Tuesday (Sep 9) ===
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
=== Friday (Sep 12) ===
{{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.}}
* Perform the [[SPO600 Compiled C Lab|Compiled C Lab (Lab 2)]] in groups
=== Week 2 Deliverables ===
* Complete and blog your conclusion to the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
* Blog your conclusion to the [[SPO600_Compiled_C_Lab|Compiled C Lab (Lab 2)]]
== 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/caution|Old Content|This content is being updated from the Fall 2014 to the Winter 2015 version of the course.}}
{{Chris Tyler Draft}}
{{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.}}
== 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)|Computer Architecture Overview]]||[[#Week 1 Deliverables|Set up accounts, and blog a comparision of code reviews in two communities (Lab 1).]]
|-
|2||Jan 19||[[#Tuesday (Jan 20)|Compiled C Lab (Lab 2)]]||[[#Thursday (Jan 22)|Prepare a presentation on a selected aspect of assembly language]]||[[#Week 2 Deliverables|Blog a commentary on the Compiled C Lab (Lab 2), and be prepared to give your presentation.]]
|-
|3||Jan 26||[[#Tuesday (Jan 27|Assembly language presentations]]||[[#Thursday (Jan 29)|Assembly language presentations]]||[[#Week 3 Deliverables|Blog about your assembly language presentation.]]
|-
|4||Feb 2||[[#Tuesday (Feb 3)|Assembly lab (Lab 3)]]||[[#Thursday (Feb 5)|Inline assembler / Potential project triage - Scan the potential project list to find out about the packages]]||[[#Week 4 Deliverables|Blog post about the assembly lab (Lab 3) and what you found in the potential projects.]]
|-
|5||Feb 9||colspan="2" align="center"|Linaro Connect - No classes scheduled - '''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)|Compiler intrinsics / Find the platform-specific code in 3 packages (Lab 4).]]||[[#Friday (Oct 10)|Group hack session - Picking your packages.]]||[[#Week 6 Deliverables|Blog about the platform-specific code in 3 packages (Lab 4) and the packages you selected.]]
|-
|7||Oct 13||[#Tuesday (Oct 15)|[[#Tuesday (Oct 14)|Benchmarking and Profiling]]||[[#Friday (Oct 17)|Group hack session - baseline builds, benchmarks, and profiling]]||[[#Week 7 Deliverables|Blog about your baseline data.]]
|-style="background: #f0f0ff"
|Study Week||Oct 20||colspan="3" align="center"|Study Week<br />'''[http://fsoss.ca FSOSS 2014] on Thursday-Friday'''
|-
|8||Oct 27||[[#Tuesday (Oct 28)|Working with the Code]]||[[#Friday (Oct 31)|Group hack session - Profiling]]||[[#Week 8 Deliverables|Blog about your progress.]]
|-
|9||Nov 3||[[#Tuesday (Nov 4)|Profiling review]]||[[#Friday (Nov 11)|Group hack session]]||[[#Week 9 Deliverables|Post baseline stats for your software.]]
|-
|10||Nov 10||[[#Tuesday (Nov 11)|Presentations]]||[[#Friday (Nov 14)|AArch64 on x86_64 / Hack session]]||[[#Week 10 Deliverables|Blog about your project status - 1st project marks.]]
|-
|11||Nov 17||[[#Tuesday (Nov 18)|Discussion and hack session]]||[[#Friday (Nov 21)|Discussion and hack session: Commercial vs. Technical Reality]]||[[#Week 11 Deliverables|Upstream your work and blog about it]]
|-
|12||Nov 24||[[#Tuesday (Nov 25)|Project Update Presentations]]||[[#Friday (Nov 28)|Discussion and hack session]]||[[#Week 12 Deliverables|Blog about your project status - 2nd project marks.]]
|-
|13||Dec 1||[[#Tuesday (Dec 2)|Discussion and Hack Session]]||[[#Friday (Dec 5)|Discussion and Hack Session]]||Code accepted upstream. Blog about it!
|-style="background: #f0f0ff"
|Exam Week||Dec 8||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%||<strike>September 30</strike>, <strike>October 31</strike>, November 21, December 10
|-
|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%||<strike>November 11</strike> (15%), November 25 (20%), December 10 (25%)
|}
== Week 1 ==
=== Friday (Sep 5) ===
==== Introduction to the Problem ====
* Most software is written in a '''high-level language''' which can be compiled into [[Machine Language|machine code]] for a specific architecture. 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).
* There are over 1400 software packages/modules present in GNU Linux systems which contain architecture-specific [[Assembly Language|assembly language code]] or have other portability issues. Most of these packages cannot be built on Aarch64 systems without modification.
==== Course Projects ====
In this course, you will:
# Select two software packages from a list compiled by Steve Macintyre of Linaro. Each of the packages on this list contains assembly language code which is platform-specific.
# Prepare a fix/patch for the software so that it will run on 64-bit ARM systems (aarch64). This may be done at either of two levels:
## Port - Add additional assembly language code for aarch64 (basic solution).
## Make Portable - Remove architecture-specific code, replacing it with compiler intrinsics or high-level code so that the software will successfully build on multiple platforms.
# Benchmark - Prove that your changes do not cause a performance regression on existing platforms, and that (ideally) it improves performance.
# Upstream your Code - Submitting 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)]] which is homework due Week 2).
=== 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 [[Fall 2014 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]].
# [[SPO600 Host Setup|Set up a Fedora 20 system]].
== Week 2 ==
=== Tuesday (Sep 9) ===
* [[Computer Architecture]] overview (see also the [[:Category:Computer Architecture|Computer Architecture Category]])
=== Friday (Sep 12) ===
{{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.}}
* Perform the [[SPO600 Compiled C Lab|Compiled C Lab (Lab 2)]] in groups
=== Week 2 Deliverables ===
* Complete and blog your conclusion to the [[SPO600 Code Review Lab|Code Review Lab (Lab 1)]].
* Blog your conclusion to the [[SPO600_Compiled_C_Lab|Compiled C Lab (Lab 2)]]
== 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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