Date: Fri, 20 Jul 2012 18:26:50 -0400 From: Richard Yao <ryao@gentoo.org> To: Adrian Chadd <adrian@freebsd.org> Cc: "hackers@FreeBSD.org" <hackers@freebsd.org>, current@freebsd.org Subject: Re: Awful FreeBSD 9 block IO performance in KVM Message-ID: <5009DB2A.7070408@gentoo.org> In-Reply-To: <CAJ-VmonynbAq8XaV_-dM7aEpQ1p33P3vHA1TMjsDs=ipXOsoTw@mail.gmail.com> References: <50085193.6030203@gentoo.org> <CAJ-VmonynbAq8XaV_-dM7aEpQ1p33P3vHA1TMjsDs=ipXOsoTw@mail.gmail.com>
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[-- Attachment #1 --] On 07/20/2012 03:44 PM, Adrian Chadd wrote: > 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 Dear Adrian, I am in the process of setting up a VM instance specifically for this. While installing it, I noticed that qemu-kvm printed 'lsi_scsi: error: ORDERED queue not implemented', which might be a clue as to why the block device performance is bad. Also, I will try testing raw disk IO for Ivan after I have it setup. Yours truly, Richard Yao [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBAgAGBQJQCdsqAAoJECDuEZm+6ExkMfgP/2yLB/i7yMQ94GgzPTQad1h2 2HQl4FwdH0dRIZq1qfe+CmWwHqiz5ID86SJnlGMcWyQlWI498N635XI1pTvv1Lbg dIMHwAcWKs/dR4MYmxepKBa+JVUXIcmVT6hoADRFeuaiR8Z+3j917M8FpMKWtRzH mgSs+FgvfF3zj0cbOGdbToEyJkmMpI8oBR/1GMfDqW4qdF6FBNWSf0EG+KUpVsBK RS+dC5RUzUJzCDxMUnXC9DRzEPin7RrRJKqp6rhTDofLmR14fTK4VWqx2dkRncPf UXGIV1L7M5jx3GyC67SiBiXktxPofh/IvBiKf2m5FW8IrnnpSUt6Vl6+CeU4Rr3d PakeTZlEvWXrr2R4NK5jXOrwksX3519wSesgn3kPzlVsbywBG4Wph/FowLBOvj1a Lp+xA9Z9ea0R2WRzsrjpYbqWeRKBV+Tb+bjs7NE/8LyipYiJdIyWL6V9mLoXz5Qo V2UiAZG07/d+Vw7qzSJNlaVVZ6+QAnR3e4BrVLCDBYuckwDuyqbhGpkIXeaVbZ8A oFSYLd/fj5AiBicaV+RdHL5kKRO1vJ372IFlnY670JYWI9+04kfN9mmgk19Qzzok eZVKxPLMvvLn2hEDBHRmASF1uGHk9W4c6sKJgryvmCqYRzJtpwz3G9vmycS7zyj8 i7P46ujM4EQ8I4I/l3Sg =oGTH -----END PGP SIGNATURE-----
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