Date: Fri, 20 Jul 2012 12:44:07 -0700 From: Adrian Chadd <adrian@freebsd.org> To: Richard Yao <ryao@gentoo.org> Cc: "hackers@FreeBSD.org" <hackers@freebsd.org>, current@freebsd.org Subject: Re: Awful FreeBSD 9 block IO performance in KVM Message-ID: <CAJ-VmonynbAq8XaV_-dM7aEpQ1p33P3vHA1TMjsDs=ipXOsoTw@mail.gmail.com> In-Reply-To: <50085193.6030203@gentoo.org> References: <50085193.6030203@gentoo.org>
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On 19 July 2012 11:27, Richard Yao <ryao@gentoo.org> wrote: > Dear Everyone, > > FreeBSD 9 has awful block IO performance in KVM. I have experienced it > and others have experienced it. Someone posted slides to slideshare with > benchmarks documenting it: > > http://www.slideshare.net/TakeshiHasegawa1/runningfreebsdonlinuxkvm > > Slides 13 and 20 are particular eye openers. Does anyone know what is wrong? For those watching at home - this is bad performance _with_ the virtio drivers themselves, not just with SCSI emulation. Slide 17 is very telling - the operation latency is quite high. Richard, are you able to easily test out things on FreeBSD-HEAD guest in a Linux KVM? If so, some of the storage/block/GEOM driver people may be able to step up and start offering some ideas. Thanks, Adrian
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