Winter 2015 SPO600 Weekly Schedule

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 Fall 2014 version of the weekly schedule, see Fall 2014 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.

Week	Week of...	Tuesday	Thursday	Deliverables (Summary - click for details)
1	Jan 12	Introduction to Software Porting, Portability, Benchmarking, and Optimization / How is code accepted into an open source project? (Lab 1)	Benchmarking and Profiling	Set up accounts, and blog a comparision of code reviews in two communities (Lab 1).
2	Jan 19	Working with the code / Building	Build and benchmark a portion of the LAMP stack (Lab 2)	Blog about your baseline data (Lab 2)
3	Jan 26	Profiling: Finding the pain points (Lab 3)	Computer architecture overview	Blog about the profiling results and pain points discovered (Lab 3)
4	Feb 2	Compiled C Lab (Lab 4)	Compiler optimizations	Blog a commentary on the Compiled C Lab (Lab 3).
5	Feb 9	Linaro Connect - No classes scheduled Prepare a presentation on a selected topic about platform-specific code.		Be prepared to present your topic.
6	Feb 16	Presentations on platform-specific code.	Presentations on platform-specific code.	Blog about your presentation.
7	Feb 23	Project presentations - Stage 1.	Prepare a presentation on a selected aspect of assembly language.	Blog about your project plans - this will be used to assign your 1st Project Marks. Be prepared to give your presentation.
Study Week	Mar 2	Study Week - No classes!
8	Mar 9	Assembly language presentations	Assembly language presentations	Blog about your assembly language presentation.
9	Mar 16	Assembly lab (Lab 5)	Reading reference documentation (and Lab 5 Continued)	Blog about the assembly lab (Lab 5).
10	Mar 23	Project Presentations - Stage 2	Uptreaming	Blog about your project progress - this will be used to assign your 2nd Project Marks.
11	Mar 30	Inline Assembler	Find inline assembler in 3 packages (Lab 6)	Blog about the assembler you found (Lab 6).
12	Apr 6	Discussion & Hack Session	Discussion & Hack Session	Blog about your progress.
13	Apr 13	Project Presentations - Stage 3	Wrap-up Session	Blog about your project progress - this will be used to assign your 3rd project marks.
Exam Week	Apr 20	Exam Week - No exam in this course!

Evaluation

Category	Percentage	Evaluation Dates
Communication	20%	January 31, February 28, March 27, April 22
Quizzes	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	10%	See deliverables column above.
Project work	60%	Feb 27 (15%), March 27 (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 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 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, and most hardware access should be performed through the operating system or appropriate libraries.
• A new architecture has appeared: Aarch64, which is part of ARMv8. This is the first new 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:

1. Test the performance of all or part of the LAMP stack.
2. 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.
3. Prepare a fix/patch for the software to implement that performance improvement.
4. Prove that your changes do not cause any performance regressions.
5. 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 Course Outline, and SPO600 Course Policies.

Discussion of how open source communities work

• Background for the Code Review Lab (Lab 1).

Thursday (Jan 15)

• Benchmarking and Profiling

• Profiling with gprof
  • Build with profiling enabled (use the option -pg with both gcc and ld)
  • Run the profile-enabled executable
  • Analyze the data in the gmon.out file
    • gprof nameOfBinary # Displays text profile including call graph
    • gprof nameOfBinary | gprof2dot | dot | display - # Displays visualization of call graph

Resources

• GProf Manual
• Profiling with GProf

Week 1 Deliverables

1. Set up your SPO600 Communication Tools - in particular, set up a blog and add it to Planet CDOT (via the Planet CDOT Feed List).
2. Add yourself to the Fall 2014 SPO600 Participants page (leave the projects columns blank).
3. Generate a pair of keys for SSH and email the public key to your professor.
4. Sign and return the Open Source Professional Option Student Agreement.
5. Optional but recommended: Set up a Fedora 20 system.

Week 2

Tuesday (Jan 20)

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.

Working with the Code

• Working with GIT
• 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

Thursday (Jan 22)

• Baseline Builds and Benchmarking Lab (Lab 2)

Week 2 Deliverables

• Complete and blog your conclusion to the Code Review Lab (Lab 1).
• Blog your baseline data from the Baseline Builds and Benchmarking lab (Lab 2).