[pypy-dev] Rough draft of x86-64 JIT backend GSoC proposal
jcreigh at gmail.com
Wed Mar 31 00:18:03 CEST 2010
I agree with fijal that it seems short, but I don't know what else to
=== Proposal ===
The PyPy JIT, which has shown substantial performance improvements over
other implementations of Python, including CPython and Unladen Swallow,
does not currently support the x86-64 instruction set, making it
impractical to use on 64-bit x86 systems.
My proposal is to extend the existing x86 JIT backend to support x86-64
=== Deliverables ===
Stable, tested 64-bit JIT for PyPy on Linux, Mac OS X and Windows merged
into PyPy trunk.
=== Implementation plan ===
This is not a research proposal. The goal is simply to have a PyPy JIT
that works out of the box on 64-bit CPUs, implemented as conservatively
As such, I will attempt to reuse as much of the existing x86 backend
that I can. In fact, the architectural similarities between x86 and
x86-64 are large enough that I hope to implement a unified x86/x86-64
backend with the majority of the code working for either platform.
There is an existing branch that, while very incomplete, has the
beginnings of a unified x86/x86-64 instruction encoding module, which
can encode instructions for either x86 or x86-64 in a fairly seamless
manner. I intend to use that branch as a starting point.
1. Take the existing "remove-ri386-multimethod-2" branch and use it as a
basis for instruction encoding. Modify the existing 32-bit backend to
use the new instruction encoding scheme.
2. Add 64-bit support to the backend,
A) Add tests to ensure that 64-bit instructions are being
B) Modify register allocator to use new general purpose and
floating point registers.
C) Port 32-bit specific portions of the JIT (for example, guard
failure handling) to 64-bit
3. Test 64-bit on Mac OS X and Windows, and fix inevitable issues.
If the 64-bit JIT is completed before the end of the summer, I will
spend the remainder of the time working on other 64-bit or JIT-related
aspects of PyPy, for example adapting the "asmgcc" garbage collection
strategy to 64-bit.
=== Development Workflow ===
The PyPy project makes extensive use of Subversion branches for
development, so I will follow that convention and develop the 64-bit JIT
in one or more branches.
For unit testing, I will use the py.test framework (already used
throughout PyPy), aiming for 100% test coverage.
=== About Me ===
I am a first-year Computer Science student at Flathead Valley Community
College planning to transfer to Montana State University.
I have several years of professional development experience. I am
comfortable programming in Python, C and x86 assembly.
Starting May 17th, I will be able to commit 40 hours/week to the project
until the end of August. I may travel for a few weeks at some point in
the summer, but I will have a laptop with me with the expectation of
continuing full-time work.
=== Contact information ===
Email: jcreigh at gmail.com
IRC: "jcreigh" on Freenode
Phone: <will be included in actual proposal, but pypy-dev is publicly
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