re: Severe startup latencies for Windows applications run under wine
Try oprofile instead. ( A really old intro is at http://www.winehq.org/wwn/249#oprofile%20&%20Wine )
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/
On 31 August 2011 17:25, Ben Peddell <klightspeed(a)netspace.net.au> wrote:
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.
I wonder if writing to /proc/pid/mem instead would help here then, similar to what we do in read_process_memory(). Writable /proc/pid/mem is a relatively recent feature though, you'd probably need at least a 2.6.39 kernel.
On 2011-09-01 01:25+1000 Ben Peddell wrote:
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.
Hi Ben: Let me remind you and others here why I am so interested in these results. I am a strong advocate of free software on all platforms (not just Linux) so I went out of my way to make sure my recent ephcom-2.0.2 release built and gave good test results on MinGW/MSYS/Wine (the only Windows platform accessible to me). And that complete success on one Windows platform was confirmed by somebody else on a MinGW/MSYS/Microsoft Windows XP platform. However, the 0.5-second command startup latency under Wine makes software builds under MinGW/MSYS/Wine extraordinarily inconvenient. The problem is that build systems such as autotools and cmake (and presumably the rest as well) all break down the configuration task into many tiny tasks and similarly for the build itself under make. So when each of those tiny tasks take 0.5 seconds to complete the result is an extraordinary slowdown of the build. ephcom-2.0.2 is actually a pretty simple package so this wasn't too bad an issue in that case, but to test my build environment on MinGW/MSYS/wine, I recently attempted to build cmake (a C++ application in its own right that can be built using the windows binary version of cmake). That build was a success, but the whole build took more than an hour (as opposed to ~10 minutes under Linux). (Much) worse, yet, that hour constituted a denial of service attack on the Linux box underneath (and the same for the ephcom-2.0.2 build although substantially shorter duration in that case). During that time everything on the Linux desktop slowed to a crawl. For example, in a (pysol) Linux solitaire game I attempted, each card dealt took about a second (!) to complete. Switching from one desktop to another took seconds as well. The "top" application showed that whatever resource that the build under wine was consuming was not accessible to "top"; the cpu's were idle (virtually 100 per cent idle time), there was negligible wait time, and there was nothing obviously bad in the memory use. (These results were all with Linux kernel "Linux raven 2.6.32-5-amd64 #1 SMP Fri Sep 9 20:23:16 UTC 2011 x86_64 GNU/Linux" from Debian squeeze.) I am aware that you can build Windows software directly from Linux, but I am not going to use that alternative because for potential users of my software on all Windows platforms I need to test the build system of my software in a realistic Windows environment, and Wine provides that for me. Thus, despite the current horrible inconvenience I am going to stick with attempting to build software under Wine. Nevertheless, I think until this command startup latency under Wine (and especially the corresponding denial of service attack on Linux underneath) is reduced, most developers will avoid as much as possible attempting to build their packages under Wine. In sum, from my perspective it is important for the Wine developers to figure out exactly what the issue is and deal with it. 0.5-second command startup latencies are just not acceptable for a general platform. So where do we stand in that effort to find a solution? From above, your "500 iterations took about 100s" equates to a 0.2 second component of the command start-up latency that you have identified. And WriteProcessMemory() requiring 125000 syscalls(a)0.8us = 0.1 seconds just to copy 500kB sounds really bad. Have you opened a bug report to keep track of your results? If so, I would like to add my own timing results there. If not, shall I open a bug report for my timing results that you can add to? Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________
On 17 September 2011 20:34, Alan W. Irwin <irwin(a)beluga.phys.uvic.ca> wrote:
In sum, from my perspective it is important for the Wine developers to figure out exactly what the issue is and deal with it. 0.5-second Did anyone look into writing to /proc/pid/mem like I mentioned? Aside from perhaps the kernel version requirement this should be trivial to test. (Untested patch attached.)
participants (4)
-
Alan W. Irwin -
Ben Peddell -
Dan Kegel -
Henri Verbeet