Re: [PATCH] you can use this patch to profile cygwin

[jojelino <jojelino at gmail dot com>]

On 2011-07-31 PM 5:26, Corinna Vinschen wrote:
> Erm, I tested on 32 bit.  The slowdown occured on all platforms, not
> only 64 bit.  64 bit is still only half as fast in the date loop for
> reason or reasons unknown.
>
>
> Corinna
 I used this code to profile every source compiled with -pg 
-finstrument-functions.
It had no documentation. because it existed solely for the purpose to 
breakdown  the cause of slow start.
Existing profiling code has ability to profile single-thread.so it had 
rare useful when the target is cygwin.(it spawns thread.) so i tried 
gaving them to consider threaded environment.
And modified profiling code uses instrument function to profile every 
function enter/exit. eventually, it resulted in terrible performance 
(2.42x slowdown at least)
when the profiling worker is forced to terminated( 
ExitProcess,abort,exit.. ) it notifies worker thread and joins the thread.
Also, i modified initial startup a little bit.

and here is instruction.
# apply patch
for i in thread_profile_stuff.diff thread_profile_core.diff; do patch 
-p0 <$i;done;
# pass configure parameter to build cygwin if you didn't configured it.
# make sure that cygwin is configured and can be built. from now i 
copy-paste some bunch of code.
# in i686-pc-cygwin/winsup/cygwin/Makefile, you should add CFLAGS '-pg 
-finstrument-functions' , to make new profiling code effective.
and comment out ifneq "${filter -O%,$(CFLAGS)}" "" too. it would make 
profiling code functional ( in cases you need to profile cygheap thread 
etc...)
#and use following snippet code to build new cygwin1.dll
s='';for i in boundbuffer pthread instrument kernel32 malloc_wrapper 
pseudo-reloc libstdcxx_wrapper cxx gcrt1 gmon profil mcount; do rm $i.o; 
s="${s} ${i}.o";done;  make CFLAGS='-march=-O2 -g -mfpmath=sse 
-Wno-error=unused-but-set-variable' $s -j 4;make;
#there would be no -pg -finstrument-functions in CFLAGS.
#what this does is, keep some source code from to be profiled.
and done. you got new-cygwin1.dll. rename it and try to discover what is 
the problem. because it gave gmon out like gmon.%pid.%tid.out when 
exited. you would use gprof to see report.
Regards.

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