[pypy-commit] extradoc extradoc: start working on the talk

[fijal]

Author: fijal
Branch: extradoc
Changeset: r5558:e11054f8dc0a
Date: 2015-09-30 16:25 +0200
http://bitbucket.org/pypy/extradoc/changeset/e11054f8dc0a/

Log:	start working on the talk

diff --git a/talk/pyconza2015/talk.rst b/talk/pyconza2015/talk.rst
new file mode 100644
--- /dev/null
+++ b/talk/pyconza2015/talk.rst
@@ -0,0 +1,130 @@
+
+How PyPy runs your program
+==================
+
+About me
+--------
+
+* PyPy core developer for 8 years
+
+* running consulting business baroquesoftware.com
+
+This talk
+---------
+
+The idea is to learn:
+
+* how pypy runs your programs
+
+* how to assess the performance of your program
+
+* additionally, why a lot of common folklore is not true
+
+The basics of PyPy
+------------------
+
+* python interpreter, just that
+
+* uses magic to run code faster (most of the time)
+
+* different base, not written in C
+
+PyPy - the wider angle
+----------------------
+
+* download it, should come in your distribution
+
+* x86, x86_64, arm; windows, os x, linux
+
+* open source (MIT)
+
+PyPy - usage
+------------
+
+* mostly long running server programs
+
+* call C using cffi, a lot of libraries just work
+
+* use virtualenv (you should anyway)
+
+PyPy - magic
+------------
+
+* just in time compiler, replaces bytecode to assembler under your feet
+
+* takes a while to warm up, which defeats most short running programs
+
+* most of the time faster, sometimes slower
+
+* heavily optimizing, tons of heuristics for **typical** python programs
+
+PyPy - smallish example
+-----------------------
+
+* take python code
+
+* run python in interpreted mode (slow)
+
+* run python in meta-interpreter mode (VERY SLOW)
+
+* compile to optimized assembler
+
+* repeat if necessary
+
+Tracing JIT
+-----------
+
+* follow what the program is doing
+
+* enter special mode where all the operations are recorded
+
+* compile the recorded list of operations
+
+* add a bunch of "guards" that check that we're following the correct path
+  and correct optimizations
+
+* if guard fails, jump to interpreter
+
+* if guard fails enough jump to metainterpreter
+
+* repeat until all the paths are compiled to assembler
+
+Performance
+-----------
+
+* you need a metric (response time, number of requests)
+
+* the less you're trying to measure, the better
+
+* benchmarks are a vast improvement
+
+* repeatability is the key
+
+Optimization for dummies
+-------------------------
+
+* Obligatory citation
+
+  - *premature optimization is the root of all evil* (D. Knuth)
+
+* Pareto principle, or 80-20 rule
+
+  - 80% of the time will be spent in 20% of the program
+
+  - 20% of 1 mln is 200 000
+
+* Two golden rules:
+
+  1. Identify the slow spots
+
+  2. Optimize them
+
+Guidos points about optimizing python
+-------------------------------------
+
+xxx find the link
+
+Why we're here?
+---------------
+
+yyyyy