From: Paolo Bonzini <pbonzini@redhat.com>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Anthony Liguori <aliguori@us.ibm.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
kvm-devel <kvm@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
lf-virt <virtualization@lists.linux-foundation.org>,
Anthony Liguori <aliguori@linux.vnet.ibm.com>,
target-devel <target-devel@vger.kernel.org>,
Zhi Yong Wu <wuzhy@cn.ibm.com>, Christoph Hellwig <hch@lst.de>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Subject: Re: [PATCH 0/6] tcm_vhost/virtio-scsi WIP code for-3.6
Date: Thu, 05 Jul 2012 12:22:33 +0200 [thread overview]
Message-ID: <4FF56AE9.9060201@redhat.com> (raw)
In-Reply-To: <1341453135.23954.214.camel@haakon2.linux-iscsi.org>
Il 05/07/2012 03:52, Nicholas A. Bellinger ha scritto:
>
> fio randrw workload | virtio-scsi-raw | virtio-scsi+tcm_vhost | bare-metal raw block
> ------------------------------------------------------------------------------------
> 25 Write / 75 Read | ~15K | ~45K | ~70K
> 75 Write / 25 Read | ~20K | ~55K | ~60K
This is impressive, but I think it's still not enough to justify the
inclusion of tcm_vhost. In my opinion, vhost-blk/vhost-scsi are mostly
worthwhile as drivers for improvements to QEMU performance. We want to
add more fast paths to QEMU that let us move SCSI and virtio processing
to separate threads, we have proof of concepts that this can be done,
and we can use vhost-blk/vhost-scsi to find bottlenecks more effectively.
In fact, virtio-scsi-qemu and virtio-scsi-vhost are effectively two
completely different devices that happen to speak the same SCSI
transport. Not only virtio-scsi-vhost must be configured outside QEMU
and doesn't support -device; it (obviously) presents different
inquiry/vpd/mode data than virtio-scsi-qemu, so that it is not possible
to migrate one to the other.
I don't think vhost-scsi is particularly useful for virtualization,
honestly. However, if it is useful for development, testing or
benchmarking of lio itself (does this make any sense? :)) that could be
by itself a good reason to include it.
Paolo
next prev parent reply other threads:[~2012-07-05 10:22 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1341375846-27882-1-git-send-email-nab@linux-iscsi.org>
2012-07-04 4:24 ` [PATCH 1/6] vhost: Separate vhost-net features from vhost features Nicholas A. Bellinger
2012-07-04 4:41 ` Asias He
2012-07-04 4:24 ` [PATCH 2/6] vhost: make vhost work queue visible Nicholas A. Bellinger
2012-07-04 4:24 ` [PATCH 3/6] vhost: Add vhost_scsi specific defines Nicholas A. Bellinger
2012-07-04 4:24 ` [PATCH 4/6] tcm_vhost: Initial merge for vhost level target fabric driver Nicholas A. Bellinger
2012-07-04 4:24 ` [PATCH 5/6] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN scanning Nicholas A. Bellinger
2012-07-04 4:24 ` [PATCH 6/6] virtio-scsi: Set shost->max_id=1 for tcm_vhost WWPNs Nicholas A. Bellinger
2012-07-04 14:02 ` [PATCH 0/6] tcm_vhost/virtio-scsi WIP code for-3.6 Michael S. Tsirkin
2012-07-04 14:52 ` Paolo Bonzini
2012-07-04 15:05 ` Michael S. Tsirkin
2012-07-04 22:12 ` Anthony Liguori
2012-07-05 1:52 ` Nicholas A. Bellinger
2012-07-05 10:22 ` Paolo Bonzini [this message]
2012-07-05 13:53 ` Michael S. Tsirkin
2012-07-05 14:06 ` Anthony Liguori
2012-07-05 14:32 ` Paolo Bonzini
2012-07-05 21:00 ` Michael S. Tsirkin
[not found] ` <4FF59F6B.2000101@us.ibm.com>
2012-07-05 14:40 ` Michael S. Tsirkin
2012-07-05 14:47 ` Paolo Bonzini
2012-07-05 17:26 ` Michael S. Tsirkin
2012-07-06 3:01 ` Nicholas A. Bellinger
[not found] ` <1341543672.23954.285.camel@haakon2.linux-iscsi.org>
[not found] ` <1341553397.3023.16.camel@dabdike.hilton.com>
2012-07-06 9:13 ` SCSI Performance regression [was Re: [PATCH 0/6] tcm_vhost/virtio-scsi WIP code for-3.6] Nicholas A. Bellinger
[not found] ` <1341582550.2941.10.camel@dabdike>
2012-07-06 18:21 ` Nicholas A. Bellinger
2012-07-06 20:30 ` [Ksummit-2012-discuss] " Christoph Lameter
[not found] ` <alpine.DEB.2.00.1207061528520.2656@router.home>
2012-07-06 22:06 ` Nicholas A. Bellinger
2012-07-06 3:38 ` [PATCH 0/6] tcm_vhost/virtio-scsi WIP code for-3.6 Nicholas A. Bellinger
2012-07-06 5:39 ` Paolo Bonzini
2012-07-05 17:53 ` Bart Van Assche
[not found] ` <4FF5D494.2090707@acm.org>
2012-07-05 19:57 ` Bart Van Assche
2012-07-10 0:29 ` Nicholas A. Bellinger
2012-07-05 2:01 ` Nicholas A. Bellinger
[not found] ` <1341453665.23954.224.camel@haakon2.linux-iscsi.org>
2012-07-05 9:31 ` Michael S. Tsirkin
2012-07-06 3:13 ` Nicholas A. Bellinger
[not found] ` <1341375846-27882-6-git-send-email-nab@linux-iscsi.org>
2012-07-04 14:50 ` [PATCH 5/6] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN scanning Paolo Bonzini
[not found] ` <1341375846-27882-7-git-send-email-nab@linux-iscsi.org>
2012-07-04 14:50 ` [PATCH 6/6] virtio-scsi: Set shost->max_id=1 for tcm_vhost WWPNs Paolo Bonzini
2012-07-05 2:05 ` Nicholas A. Bellinger
2012-07-05 6:42 ` Paolo Bonzini
[not found] ` <1341375846-27882-5-git-send-email-nab@linux-iscsi.org>
2012-07-05 17:47 ` [PATCH 4/6] tcm_vhost: Initial merge for vhost level target fabric driver Bart Van Assche
[not found] ` <4FF5D31F.90404@acm.org>
2012-07-05 17:59 ` Bart Van Assche
2012-07-04 4:24 [PATCH 0/6] tcm_vhost/virtio-scsi WIP code for-3.6 Nicholas A. Bellinger
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