Re: Awful FreeBSD 9 block IO performance in KVM
- Original Message - From: Dieter BSD dieter...@engineer.com To: hack...@freebsd.org, curr...@freebsd.org Sent: Sunday, July 22, 2012 1:19:32 AM Subject: Re: Awful FreeBSD 9 block IO performance in KVM da0: 3.300MB/s transfers da0: Command Queueing enabled root@freebsd:/root # dd if=/dev/zero of=/dev/da1 bs=16384 count=262144 4294967296 bytes transferred in 615.840721 secs (6974153 bytes/sec) 1) Does a larger block size (bs=1m) help? 2) That's roughly the speed I'd expect without queueing. Is it really making effective use of queueing, or is something limiting queueing to one transfer at a time? The likely fix here is basically do vtblk_startio() in a separate kproc that vtblk_strategy() enqueues bio's to. This has been on my todo for a while, but haven't had the time. Also, the use of bioq_disksort() probably doesn't gain much for virtualized disks, but I never found much of a difference in my testing. ___ freebsd-hack...@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: Awful FreeBSD 9 block IO performance in KVM
On 19 July 2012 11:27, Richard Yao r...@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 ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: Awful FreeBSD 9 block IO performance in KVM
On 07/20/2012 03:44 PM, Adrian Chadd wrote: On 19 July 2012 11:27, Richard Yao r...@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 signature.asc Description: OpenPGP digital signature
Re: Awful FreeBSD 9 block IO performance in KVM
On 20 July 2012 15:26, Richard Yao r...@gentoo.org wrote: 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. Thanks for setting this up. Setting up an easily reproducible environment is by far the biggest and most helpful step here. Adrian ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
