Fall 2015 SPO600 Weekly Schedule
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 which will be added below as the course proceeds -- especially for the Deliverables column.
Evaluation
| Category | Percentage | Evaluation Dates |
|---|---|---|
| Communication | 20% | September 30, October 31, November 30, December 11 |
| 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% | Oct 20 (15%), Nov 13 (20%), December 11 (25%) |
Week 1
Tuesday (Sep 8)
No class due to the Experience Seneca orientation program.
Friday (Sep 11)
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- Most of the historical reasons for including assembler are no longer valid.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:
- Help develop a test framework for C compiler optoins.
- Select an open source software package.
- Determine the impact of various C compiler options on the selected software.
- Make recommendations for the C compiler options/flags to be used on the AArch64 architecture.
- Prepare a fix/patch for the software to set the recommended options when compiling on AArch64 and submit these changes upstream, OR report to upstream that they are already using the optimal flags.
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.
- Optional: You can participate in the Linaro Code Porting/Optimization contest. For details, see the YouTube video of Jon "maddog" Hall and Steve Mcintyre at Linaro Connect USA 2013.
Discussion of how open source communities work
- Background for the Code Review Lab (Lab 1).
Week 1 Deliverables
- Set up your SPO600 Communication Tools - in particular, set up a blog and add it to Planet CDOT (via the Planet CDOT Feed List).
- Add yourself to the Fall 2015 SPO600 Participants page (leave the projects columns blank).
- Generate a 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: Set up a personal Fedora system.
- Optional but recommended: Purchase an AArch64 development board.
Week 2
Tuesday (Sep 15)
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.
- Compiled C Lab (Lab 2)
- Sheets from Last Week
- Open Source Student Agreement
Friday (Sep 18)
- Introductions
- Compiler Optimizations
- Introduction to the Compiler Options Presentation
Week 2 Deliverables
- Blog about your Code Review Lab (Lab 1) and Lab 2 experience and results. For lab 2, consider the optimizations and transformations that the compiler performed. Remember that these posts (as all of your blog posts) will be marked both for communication (clarity, quality of writing (including grammar and spelling), formatting, use of links, completeness) and for content (lab completion and results). Your posts should contain both factual results as well as your reflections on the meaning of those results, the experience of performing the lab, and what you have learned.
Week 3
This week your professor is at Linaro Connect, an engineering conference run by Linaro - a distributed not-for-profit collaborative technology company focused on Linux on ARM.
Week 3 Deliverables
- Be prepared to give your presentation on Tuesday of next week (September 29).
Week 4
Tuesday (Sep 29)
- Presentations
Friday (Oct 2)
- Presentations
- Introduction to ARM64 hardware
- Algorithm Selection Lab (Lab 3)
Week 4 Deliverables
- Blog your presentation, incorporating any feedback and Q&A input that was given during/after the presentation in class.
Week 5
Tuesday (Oct 6)
- Class discussion/hacking on Lab 3.
Friday (Oct 9)
- More on Lab 3
- Discussion of Benchmarking
Week 5 Deliverables
- Blog your Lab 3 results.
Week 6
Tuesday (Oct 13)
- Discussion of benchmarking
- Control of variables
- Competition for system resources
- Repeatability
- Control of variables
- Planning for a Compiler Options Test Framework
Friday (Oct 16)
- Compiler Options Framework
- Divide up tasks
- Start development
Week 6 Deliverables
- Blog your recommendations for the test framework design.
Week 7
Tuesday (Oct 20)
- Build the Compiler Options Test Framework
Friday (Oct 23)
- Project selection
- Your task over reading week: Become an expert in building your selected software, and then make it work with the Compiler Options Test Framework
Week 7 Deliverables
- Blog about the compiler options framework, and your work on that project.
- Blog about your selected project.
Week 8
Tuesday (Nov 3)
- No class scheduled - your prof is in Whitehorse, YK at an NSERC workshop.
- Please work on your project, and be ready to present on Friday.
Friday (Nov 6)
- Present your Stage I results for your project.
Week 8 Deliverables
- Blog about your stage I project results. This will be used to assign the first marks for your project.
Week 9
Tuesday (Nov 10)
- Computer Architecture overview (see also the Computer Architecture Category)
Friday (Nov 13)
- Assembly Language Lab (Lab 4)