Laurent Vivier wrote: > Avi Kivity wrote: > >> Aurelien Jarno wrote: >> >>> >>> >>>> What is your disk image file format, or are you using a partition? >>>> >>>> >>> I am using a raw image file on an ext3 partition. >>> >>> >>> >>>> Do the results change (on kvm-14) if you pin the guest to a core with >>>> 'taskset 1 qemu ...' >>>> >>>> >>> Bingo. It now works even faster than kvm-13! >>> >>> real 0m22.307s >>> user 0m13.935s >>> sys 0m4.720 >>> >>> >>> >> I'm guessing this is due to the glibc aio implementation, which uses >> threads instead of true aio. The threads may cause the vcpu to migrate >> frequently from one code to another. >> >> There are two possible solutions: >> >> - use native aio from http://www.bullopensource.org/posix/. I think >> the aio signal patches are not yet in, so this may not work. >> - teach the scheduler about the cost of migrating vcpus >> The first approach will solve itself eventually, though slowly if the >> current slow rate of aio merging continues. We'll have to do the second. >> >> > > if you prefer the first one, Sébastien will release very soon aio patches for > 2.6.20 with an up-to-date libposix-aio. >
Hi Laurent, I gave that a shot a little bit ago. Ran into two problems. 1) Couldn't avoid linking to -lrt as QEMU uses time functions from it. 2) While I could get things compiling (with patches), QEMU would SEGV almost immediately. Could you guys maybe give compiling QEMU w/libposix-aio a shot? I'm really interested to see if it makes a difference. Regards, Anthony Liguori > [advertising] Keep an eye on the bullopensource website. [/advertising] > :-P > > Regards, > Laurent > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > ------------------------------------------------------------------------ > > _______________________________________________ > kvm-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/kvm-devel > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
