I realise that 1.0.16 is currently trying to be released and that these patches won't get looked at until after that has happened. I'm away from the office for the next couple of weeks so thought it was worth sending this patch series for people to look at if they get time while I'm away.
A while ago I mentioned that I thought that I was seeing performance issues due to all the fake FD logic in the Windows backends. This patch series makes these changes. This series is actually a group of related changes. Patches 1, 2 and 7 add some additional tests and testlib functionality. Patch 3 adds a new event API which provides FDs on POSIX systems but HANDLES on Windows systems. Patch 4 changes the core code to make use of the new FD/HANDLE type. Patch 5 and 6 change the Windows backends over to using the FD/HANDLE type. While developing these patches I noticed that the Windows backends have a bug where if you get more than MAXIMUM_WAIT_OBJECTS pollfds then any attempt at a synchronous transfer will hang. The problem is that the handling of events starts to fail when too many transfers have been submitted. This is impossible to recover from as event handling needs to occur to remove the pollfds for cancelled/completed transfers. Patches 8 and 9 modify the core code to allow pre-reserving of pollfds and limiting the total number of concurrent pollfds. Instead of failing in handling events with high numbers of pollfds this makes it possible to fail the submission of the transfer. Patch 10 makes use of pre-reserving of pollfds in the Windows backends. Finally patch 11 enables limiting the number of concurrent pollfds on Windows platforms. As for the original reason for this patch series, our actual performance uses cases have improved by about 5% on WinCE through these changes. Sadly the simple performance tests I created don't show any improvement as they are limited by IO scheduling, not CPU usage. Regards, Toby ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
