User:LYH

GSoC 2013 - Application

A: An introduction

• Please describe yourself in three sentences, one of them regarding your current studies.

I am LYH, studying Computer Sciense and Information Management. I am also a technical enthusiast. My interest includes compiler, run time system and operating system.

• Which languages do you speak?

1. Mandarin (native)
2. English

• What's your overall background?

Computer Sciense and Information Technology

• Why do you want to participate in the Google Summer of Code? What do you hope to gain by doing so?

I am a technical enthusiast and has been using several opern source project in my research. So I want to contribute to open source organization via participating GSoC. In addition to the opportunity that cooperate with open source group, I hope to gain experience with Octave IR, JITC internal and JIT optimizations (trace/method-based compilation … etc).

• Please also describe your previous experience with the GSoC.

I applied GSoC last year so I am familiar with how this program goes.

• Why are you choosing Octave?

I noticed that Jordi Gutiérrez Hermoso post an idea related to JIT compiling on GSoC discuss group. Since I have some experience using LLVM JIT to improve runtime system performance. I want to improve Octave JITC and further make it my research thesis.

C: Contact

• Please state the (unique and identical where possible) nick you use on IRC and any other communication channel related to Octave.

My nickname is LYH.

• Which time zone do you live in? Will that change over GSoC duration?

My time zone is UTC+8 during the whole GSoC.

• Please state the timeframe (in UTC+0) when you feel most comfortable working during GSoC. Where are your time buffers?

I usually code around 9:00 to 18:00 and could also try end later (~20:00) for need.

E: Coding experience

• Please describe your experience with C++, Octave or Matlab m-scripts, OpenGL and Qt.

I have been programming in C/C++ for six years. When I was a freshman, I got the highest score in my C++ programing class. My technical experience comes from not only studies but also projects. Here are the C/C++ projects I finished before:

1. Instant Manager - Use C, POSIX Threads, BSD Socket and GTK+ to construct a server and a client. The project ranked first in Computer Networks class
2. VNC (Virtual Network Computing) on EFI (Extensible Firmware Interface) - Under bios development environment, I Implement full VNC client on EFI.

On the other hand. I have taken a numeraical methods course before. I use Matlab to implement algorithm about solving one variable equations, interpolation and polynomial approxiamation, numerical differentiation and intergratation … etc. Matlab m-scripts is not new to me.

• Please describe your experience with other programming languages.

I used Verilog to implement a MIPS CPU with multiple-stage pipeline and cache before. Hardware description language is not difficult to me. Besides, I have some experience in Java and C#. Because my primary working environment is Linux, I also use shell script and Perl to simplify daily routine.

• Please describe your experience with being in a development team. Do you have experience working with open source or free projects?

I have experience working with QEMU and have submitted several patches.

• Please describe the biggest project you have written code for and what you learned by doing so. Also describe your role in that project over time.

My biggest project is “VNC (VirtualNetwork Computing) on EFI (Extensible Firmware Interface)”. We can remote control the other computer without entering OS. As far as I know, there is no one do the project I did. So I met many problems and there was no relevant information on web. I needed to rely on my background knowledge about BIOS and System Software and solved these issues by myself. I learned not only EFI skill but also the ability to find the solution of problems during the project.

• Please state the commits and patches you already contributed to Octave.

Octave JIT doesn’t work with LLVM 3.2 because LLVM API incoherence. I have submited a patch to resolve this. https://savannah.gnu.org/bugs/index.php?38564

F: Feeling fine

• Please describe (in short) your experience with the following tools:

• IRC and mailing lists

I have used IRC and mailing lists for several years. In fact, I have talked with Octave mentor about my project on IRC already.

• Mercurial or other source code management systems

I usually use Git and Subversion. But I think it may not too dificult to migrate to Mercurial. And I have used hg to format my patch submitted to Octave.

• Mediawiki or other wiki software

None before. But I use it when I post this proposal :)

• make, gcc, gdb or other development tools

I use make to automate build process, gcc to compile and gdb to debug almost erery day. Besides these development tools. I also use Cmake for cross platform build system, clang/LLVM to compile. Learning new development tools is not hard to me.

• What will make you actively stay in our community after this GSoC is over?

In fact, a summer is too short to implement all my idea. I would need to continue contributing to complete all my goal. On the other hand, The project I proposed has highly relationship with my field of study (LLVM, compiler, interpreter). So I am willing to join Octave JIT project constantly.

O: Only out of interest

• Did you ever hear about Octave before?

Yes I did.

• • If so, when and where? How far have you been involved already?

I noticed Octave when I used proprietary Matlab in my school last year.

• • What was the first question concerning Octave you could not find an answer to rather quickly?

The build process. I did not know that I need run ./bootstrap first until I read etc/HACKING. Because I usually run autogen and configure directly.

P: Prerequisites

• Please state the operating system you work with.
  • If you have access to more than one, please state them and the conditions under which you are granted this access.

Usually Linux. But sometimes I work with Mac OSX and Windows if I need to test a program on variant platforms.

• Please estimate an average time per day you will be able to (if separated) access
  • an internet connection

Disconnect when I sleep.

• • a computer

All the time.

• • a computer with your progressing work on

More than 40 hours per week.

• Please describe the degree up to which you can install new software on computers you have access to.

I have my own macbook. So I could install all softwares I need.

S: Self-assessment

• Please describe how useful criticism looks from your point of view as committing student.

Concrete and clear. Sometimes with example.

• How autonomous are you when developing?

Give me a project direction. I could find what I need from Google, Stack Overflow, IRC and mailing list. If information is not available on web or book, I would rely on my background knowledge to analyze problem and further solve it.

• Do you like to discuss changes intensively and not start coding until you know what you want to do?
• Do you like to code a proof of concept to 'see how it turns out', modifying that and taking the risk of having work thrown away if it doesn't match what the project or original proponent had in mind?

I like to dicuss direction first and reinterpret in my words. Then ask others whether my understanding is correct. And I would start writing small program to prove my concept. If the work doesn’t match the goal, I would thrown it away early rather then coding for thousands of code and hard to debug.

Y: Your task

• Did you select a task from our list of proposals and ideas?

Yes I did.

• If yes, what task did you choose? Please describe what part of it you especially want to focus on if you can already provide this information.

   http://wiki.octave.org/Summer_of_Code_Project_Ideas#Improve_JIT_compiling

I selected “Improveing JIT compiling” project, focusing on “Enhance JITC functionality” and “Migrate from LLVM JIT to LLVM MCJIT”. Current JITC lacks some feature: Functions and exponents (e.g. 2^z) cannot compile with the JITC. I want to concentrate on expanding JITC to handle this non-trivial but fundamental case.

Second, I would begin to migrate from JIT to MCJIT. JITC use JIT now, however LLVM community has no longer maintained JIT and move to MCJIT. I think we could move to MCJIT as well (but still support JIT). This is really important if we want to get the benefit from LLVM subsequently.

When all essential case is added, I would try to implement some JIT related optimization into JITC (like trace/method-based JIT).

• Please provide a rough estimated timeline for your work on the task. This should include the GSoC midterms and personal commitments like exams or vacation ("non-coding time"). Optionally include two or three milestones you expect.

During the GSoC period. I would focus on "Enhance JITC functionality". "Migrate from LLVM JIT to LLVM MCJIT" would be completed in free time.

• Community Bonding Period (May 27 - Jun 16)

Get to know mercury, octave JITC code base. Deploy development environment and create a wiki page/blog to record progress.

• Week 1 (Jun 17 - Jun 23)

Write a piece of code to prove how JITC compile functions.

• Week 2,3 (Jun 24 - Jul 7)

Implement the functionality that JITC compile functions.

• Week 4,5 (Jul 8 - Jul 21)

Write test-case, test and debug.

• Week 6 (Jul 22 - Jul 28)

Write document, wiki and prepare for midterm evaluation.

• Week 7 (Jul 29 - Aug 4)

Write a piece of code to prove how JITC compile exponents.

• Week 8,9,10,11 (Aug 5 - Sep 1)

Implement the functionality that JITC compile exponents.

• Week 12,13 (Sep 2 - Sep 15)

Write test-case, test and debug.

• Week 14 (Sep 16 - Sep 22)

Write document, wiki and prepare for final evaluation.

• Future (Sep 23 - )

Implement JIT related optimizations into JITC