Sessions at PyCon US 2012 about PyPy

Wednesday 7th March 2012

• How to get the most out of your PyPy

  by Alex Gaynor, Maciej Fijalkowski and Armin Rigo

  For many applications PyPy can provide performance benefits right out of the box. However, little details can push your application to perform much better. In this tutorial we'll give you insights on how to push pypy to it's limites. We'll focus on understanding the performance characteristics of PyPy, and learning the analysis tools in order to maximize your applications performance.

  We aim to teach people how to use performance tools available for PyPy as well as to understand PyPy's performance characteristics. We'll explain how different parts of PyPy interact (JIT, the garbage collector, the virtual machine runtime) and how to measure which part is eating your time. We'll give you a tour with jitviewer which is a crucial tool for understanding how your Python got compiled to assembler and whether it's performing well. We also plan to show potential pitfalls and usage patterns in the Python language that perform better or worse in the case of PyPy.

  We'll also briefly mention how to get your application running on PyPy and how to avoid common pitfalls there, like reference counting or relying on C modules.

  This tutorial is intended for people familiar with Python who have performance problems, no previous experience with PyPy is needed. We ask people to come with their own problems and we'll provide some example ones. Attendees should have the latest version of PyPy preinstalled on their laptops.

  • PyPy
  • Python

  At 1:20pm to 4:40pm, Wednesday 7th March

  In H1, Santa Clara Convention Center

  Coverage video

Thursday 8th March 2012

• High Performance Python I

  by Ian Ozsvald

  At EuroPython 2011 I ran a very hands-on tutorial for High Performance Python techniques. This updated tutorial will cover profiling, PyPy, Cython, numpy, NumExpr, ShedSkin, multiprocessing, ParallelPython and pyCUDA. Here's a 55 page PDF write-up of the EuroPython material: http://ianozsvald.com/2011/07/25...

  At EuroPython 2011 I ran a very hands-on tutorial for High Performance Python techniques. This updated tutorial will cover:

  • profiling with cProfile, run_snake and line_profiler
  • PyPy
  • Cython
  • numpy with and without vectors
  • NumExpr
  • ShedSkin Py->C++ compiler
  • multiprocessing for multi-core
  • ParallelPython for multi-machine
  • pyCUDA demos

  I plan to expand the original material and to maybe also cover other tools like execnet and PyPy-numpy.

  • Performance
  • Profiling
  • PyPy
  • Python

  At 9:00am to 12:20pm, Thursday 8th March

  In D2, Santa Clara Convention Center

  Coverage video handout write-up slide deck

Saturday 10th March 2012

• Why PyPy by example

  by Alex Gaynor, Maciej Fijalkowski and Armin Rigo

  One of the goals of PyPy is to make existing Python code faster, however an even broader goal was to make it possible to write things in Python that previous would needed to be written in C or other low-level language. This talk will show examples of this, and describe how they represent the tremendous progress PyPy has made, and what it means for people looking to use PyPy.

  In this talk we'll talk about PyPy's present status and for what kinds of applications it might be useful. We'll also show examples of things that are possible with PyPy that were impossible to do with Python before, like real time video processing done in pure python. Our objective with each of the examples will be to highlight the type of work that is sped up and why this represents both a boon for existing Python programmers, as well as an opportunity for Python to expand to new audiences.

  We'll also explain a bit PyPy's accomplishements in the passing year that make all of this possible, current status, its goals and the near future.

  • PyPy

  At 10:25am to 11:05am, Saturday 10th March

  In E1, Santa Clara Convention Center

• How the PyPy JIT works

  by Benjamin Peterson

  The Python community is abuzz about the major speed gains PyPy can offer pure Python code. But how does PyPy JIT actually work? This talk will discuss how the PyPy JIT is implemented. It will include descriptions of the tracing, optimization, and assembly generation phases. I will demonstrate each step with a example loop.

  Strictly speaking, PyPy doesn't have a JIT; it has a JIT generator. I will describe how the JIT is generated during the translation of the interpreter as well as the advantages of the meta-JIT method.

  Next, we'll explore tracing, in which the JIT records operations in a hot loop. I'll introduce the meta interpreter and the JIT IR (intermediate representation).

  Optimizations are the next step of JITing. The focus will be on the most important optimizations for dynamic languages: virtuals and virtualizables. However, PyPy also includes the standard set of compiler peephole optimizations, like strength reduction, and well as some more complicated loop optimizations, like constant hoisting.

  The final topic will be assembly generation. We'll see register allocation and how specific high-level Python operations are compiled down to tight x86 instructions.

  Time permitting, additional topics may include how the garbage collector is integrated with the JIT and how the JIT bails back to the interpreter when a guard fails.

  Along the way, I will demonstrate how each phase of JITing acts on an example Python loop. This will also allow me to introduce the jitviewer, a program to view how PyPy is compiling your loops.

  • PyPy

  At 11:05am to 11:45am, Saturday 10th March

  In E1, Santa Clara Convention Center