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From: Bart Van Assche <bvanassche@acm.org>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	Anthony Liguori <aliguori@us.ibm.com>,
	kvm-devel <kvm@vger.kernel.org>,
	linux-scsi <linux-scsi@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>,
	Paolo Bonzini <pbonzini@redhat.com>,
	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 19:57:37 +0000	[thread overview]
Message-ID: <4FF5F1B1.8030702@acm.org> (raw)
In-Reply-To: <4FF5D494.2090707@acm.org>

On 07/05/12 17:53, Bart Van Assche wrote:

> On 07/05/12 01:52, Nicholas A. Bellinger wrote:
>> 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
> 
> These numbers are interesting. To me these numbers mean that there is a
> huge performance bottleneck in the virtio-scsi-raw storage path. Why is
> the virtio-scsi-raw bandwidth only one third of the bare-metal raw block
> bandwidth ?


(replying to my own e-mail)

Or maybe the above numbers mean that in the virtio-scsi-raw test I/O was
serialized (I/O depth 1) while the other two tests use a large I/O depth
(64) ? It can't be a coincidence that the virtio-scsi-raw results are
close to the bare-metal results for I/O depth 1.

Another question: which functionality does tcm_vhost provide that is not
yet provided by the SCSI emulation code in qemu + tcm_loop ?

Bart.

  parent reply	other threads:[~2012-07-05 19:57 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
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 [this message]
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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