Severe startup latencies for Windows applications run under wine

[Ben Peddell]

On 31/08/2011 3:12 AM, Dan Kegel wrote:
> Try oprofile instead.
> 
> ( A really old intro is at
> http://www.winehq.org/wwn/249#oprofile%20&%20Wine )
> 

Using oprofile, testing 500 iterations of ExitProcess.exe with
msys-bash under wine:

About 2/3 of the active processor time was in wineserver.
About 90% of that was spent in the kernel.
At least 50% of that time was spent in code related related to
ptrace(), which is ultimately called by
wineserver::write_process_memory().

The other 1/3 of the active processor time was in wine-preloader.
About 70% of that was spent in the kernel.

500 iterations took about 100s to complete at about 100% usage of 1
CPU core.

msys-bash uses WriteProcessMemory() to copy 500kB during an emulated
fork.  This equates to about 125000 ptrace(PTRACE_POKEDATA,...)
syscalls, each of which takes about 0.8us on linux 2.6.38.

-- 
Ben Peddell
IT Support Bowen, Collinsville, Proserpine and Home Hill Catholic schools
http://klightspeed.killerwolves.net/