[Python-Dev] Python 2.4, VS 2005 & Profile Guided Optmization (original) (raw)

Trent Nelson tnelson at onresolve.com
Sun Jul 23 19:42:59 CEST 2006

Hi,

Has anyone else built Python with Visual Studio 2005 and played around with Profile Guided Optimization? I had to build Python from source w/ VS 2005 as I had a few .pyd's built with VS 2005 that I wanted to load; I ended up playing around with Profile Guided Optimization, running ``python.exe pystones.py'' to collect call-graph data after python.exe/Python24.dll had been instrumented, then recompiling with the optimizations fed back in.

Results were interesting, an average speedup of around 33% was noticeable:

ActiveState 2.4.3 python.exe:

C:\Python24>python.exe Lib\test\pystone.py
Pystone(1.1) time for 50000 passes = 0.980119 This machine

benchmarks at 51014.2 pystones/second

The python compiled from branches/release24-maint with VS 2005 + profile guided optimization:

C:\Python24>python.exe Lib\test\pystone.py
Pystone(1.1) time for 50000 passes = 0.73261 This machine benchmarks

at 68249.2 pystones/second

Is there any motivation in the Win32 Python dev camp to switch from VC6 to VS 2005?

FWIW, although there were a shed-load of warnings when compiling python and pythoncore (and a lot more errors when compiling other modules), I only had to apply one patch to get it working well enough to run pystone.py. Without this patch, the VC8 CRT aborts at runtime as soon as an invalid signal is passed to signal(); which is inevitable given the current code in the initsignal() method:

for (i = 1; i < NSIG; i++) {
    void (*t)(int);
    t = PyOS_getsig(i);

Regards,

Trent.

-- http://www.onresolve.com

Index: signalmodule.c

--- signalmodule.c (revision 47196) +++ signalmodule.c (working copy) @@ -280,7 +280,21 @@ {NULL, NULL} /* sentinel */ };

+#define WIN32VS2005HACK +#ifdef WIN32VS2005HACK +#include <stdio.h> +#include <stdlib.h> +#include <crtdbg.h> +void dummy_handler(const wchar_t *exp,

+{

+} +#endif + PyDoc_STRVAR(module_doc, "This module provides mechanisms to use signal handlers in Python.\n
\n
@@ -339,6 +353,12 @@ goto finally; Py_INCREF(IntHandler);

+#ifdef WIN32VS2005HACK

+#endif + + Handlers[0].tripped = 0; for (i = 1; i < NSIG; i++) { void (*t)(int);

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