From: Rolf Eike Beer <eike-kernel@sf-tec.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
gaowanlong@cn.fujitsu.com, hutao@cn.fujitsu.com,
linux-scsi@vger.kernel.org,
virtualization@lists.linux-foundation.org, mst@redhat.com,
rusty@rustcorp.com.au, asias@redhat.com, stefanha@redhat.com,
nab@linux-iscsi.org
Subject: Re: [PATCH v2 0/5] Multiqueue virtio-scsi, and API for piecewise buffer submission
Date: Tue, 18 Dec 2012 23:18:22 +0100 [thread overview]
Message-ID: <96853954.7ghLePd55F@donald.sf-tec.de> (raw)
In-Reply-To: <1355833972-20319-1-git-send-email-pbonzini@redhat.com>
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Paolo Bonzini wrote:
> Hi all,
>
> this series adds multiqueue support to the virtio-scsi driver, based
> on Jason Wang's work on virtio-net. It uses a simple queue steering
> algorithm that expects one queue per CPU. LUNs in the same target always
> use the same queue (so that commands are not reordered); queue switching
> occurs when the request being queued is the only one for the target.
> Also based on Jason's patches, the virtqueue affinity is set so that
> each CPU is associated to one virtqueue.
>
> I tested the patches with fio, using up to 32 virtio-scsi disks backed
> by tmpfs on the host. These numbers are with 1 LUN per target.
>
> FIO configuration
> -----------------
> [global]
> rw=read
> bsrange=4k-64k
> ioengine=libaio
> direct=1
> iodepth=4
> loops=20
>
> overall bandwidth (MB/s)
> ------------------------
>
> # of targets single-queue multi-queue, 4 VCPUs multi-queue, 8 VCPUs
> 1 540 626 599
> 2 795 965 925
> 4 997 1376 1500
> 8 1136 2130 2060
> 16 1440 2269 2474
> 24 1408 2179 2436
> 32 1515 1978 2319
>
> (These numbers for single-queue are with 4 VCPUs, but the impact of adding
> more VCPUs is very limited).
>
> avg bandwidth per LUN (MB/s)
> ----------------------------
>
> # of targets single-queue multi-queue, 4 VCPUs multi-queue, 8 VCPUs
> 1 540 626 599
> 2 397 482 462
> 4 249 344 375
> 8 142 266 257
> 16 90 141 154
> 24 58 90 101
> 32 47 61 72
Is there an explanation why 8x8 is slower then 4x8 in both cases? 8x1 and 8x2
being slower than 4x1 and 4x2 is more or less expected, but 8x8 loses against
4x8 while 8x4 wins against 4x4 and 8x16 against 4x16.
Eike
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next prev parent reply other threads:[~2012-12-18 22:19 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 12:32 [PATCH v2 0/5] Multiqueue virtio-scsi, and API for piecewise buffer submission Paolo Bonzini
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 12:32 ` [PATCH v2 1/5] virtio: add functions for piecewise addition of buffers Paolo Bonzini
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 13:36 ` Michael S. Tsirkin
2012-12-18 13:36 ` Michael S. Tsirkin
2012-12-18 13:43 ` Paolo Bonzini
2012-12-18 13:43 ` Paolo Bonzini
2012-12-18 13:59 ` Michael S. Tsirkin
2012-12-18 13:59 ` Michael S. Tsirkin
2012-12-18 14:32 ` Paolo Bonzini
2012-12-18 14:32 ` Paolo Bonzini
2012-12-18 15:06 ` Michael S. Tsirkin
2012-12-18 15:06 ` Michael S. Tsirkin
2012-12-19 10:47 ` Stefan Hajnoczi
2012-12-19 10:47 ` Stefan Hajnoczi
2012-12-19 12:04 ` Paolo Bonzini
2012-12-19 12:04 ` Paolo Bonzini
2012-12-19 12:40 ` Stefan Hajnoczi
2012-12-19 12:40 ` Stefan Hajnoczi
2012-12-19 16:51 ` Michael S. Tsirkin
2012-12-19 16:51 ` Michael S. Tsirkin
2012-12-19 16:52 ` Michael S. Tsirkin
2012-12-19 16:52 ` Michael S. Tsirkin
2013-01-02 5:03 ` Rusty Russell
2013-01-02 5:03 ` Rusty Russell
2013-01-03 8:58 ` Wanlong Gao
2013-01-03 8:58 ` Wanlong Gao
2013-01-03 8:58 ` Wanlong Gao
2013-01-06 23:32 ` Rusty Russell
2013-01-06 23:32 ` Rusty Russell
2013-01-06 23:32 ` Rusty Russell
2013-01-03 9:22 ` Paolo Bonzini
2013-01-03 9:22 ` Paolo Bonzini
2013-01-07 0:02 ` Rusty Russell
2013-01-07 0:02 ` Rusty Russell
2013-01-07 14:27 ` Paolo Bonzini
2013-01-08 0:12 ` Rusty Russell
2013-01-08 0:12 ` Rusty Russell
2013-01-10 8:44 ` Paolo Bonzini
2012-12-18 12:32 ` [PATCH v2 2/5] virtio-scsi: use functions for piecewise composition " Paolo Bonzini
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 13:37 ` Michael S. Tsirkin
2012-12-18 13:37 ` Michael S. Tsirkin
2012-12-18 13:35 ` Paolo Bonzini
2012-12-18 13:35 ` Paolo Bonzini
2012-12-18 12:32 ` [PATCH v2 3/5] virtio-scsi: redo allocation of target data Paolo Bonzini
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 12:32 ` [PATCH v2 4/5] virtio-scsi: pass struct virtio_scsi to virtqueue completion function Paolo Bonzini
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 12:32 ` [PATCH v2 5/5] virtio-scsi: introduce multiqueue support Paolo Bonzini
2012-12-18 13:57 ` Michael S. Tsirkin
2012-12-18 13:57 ` Michael S. Tsirkin
2012-12-18 14:08 ` Paolo Bonzini
2012-12-18 14:08 ` Paolo Bonzini
2012-12-18 15:03 ` Michael S. Tsirkin
2012-12-18 15:03 ` Michael S. Tsirkin
2012-12-18 15:51 ` Paolo Bonzini
2012-12-18 15:51 ` Paolo Bonzini
2012-12-18 16:02 ` Michael S. Tsirkin
2012-12-18 16:02 ` Michael S. Tsirkin
2012-12-25 12:41 ` Wanlong Gao
2012-12-25 12:41 ` Wanlong Gao
2012-12-19 11:27 ` Stefan Hajnoczi
2012-12-19 11:27 ` Stefan Hajnoczi
2012-12-18 12:32 ` Paolo Bonzini
2012-12-18 13:42 ` [PATCH v2 0/5] Multiqueue virtio-scsi, and API for piecewise buffer submission Michael S. Tsirkin
2012-12-18 13:42 ` Michael S. Tsirkin
2012-12-24 6:44 ` Wanlong Gao
2012-12-24 6:44 ` Wanlong Gao
2012-12-18 22:18 ` Rolf Eike Beer [this message]
2012-12-19 8:52 ` Paolo Bonzini
2012-12-19 8:52 ` Paolo Bonzini
2012-12-19 11:32 ` Michael S. Tsirkin
2012-12-19 11:32 ` Michael S. Tsirkin
2012-12-18 22:18 ` Rolf Eike Beer
2013-01-15 9:48 ` [PATCH 1/2] virtio-scsi: split out request queue set affinity function Wanlong Gao
2013-01-15 9:48 ` Wanlong Gao
2013-01-15 9:50 ` [PATCH 2/2] virtio-scsi: reset virtqueue affinity when doing cpu hotplug Wanlong Gao
2013-01-15 9:50 ` Wanlong Gao
2013-01-16 3:31 ` Rusty Russell
2013-01-16 3:31 ` Rusty Russell
2013-01-16 3:55 ` Wanlong Gao
2013-01-16 3:55 ` Wanlong Gao
2013-02-06 17:27 ` Paolo Bonzini
2013-02-06 17:27 ` Paolo Bonzini
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