From: Paolo Bonzini <pbonzini@redhat.com>
To: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@canonical.com>
Cc: James Bottomley <JBottomley@parallels.com>,
Jens Axboe <axboe@kernel.dk>,
Linux SCSI List <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 2/2] virtio_scsi: support multi hw queue of blk-mq
Date: Tue, 11 Nov 2014 18:09:17 +0100 [thread overview]
Message-ID: <546242BD.5010902@redhat.com> (raw)
In-Reply-To: <20141110160506.GB15315@lst.de>
On 10/11/2014 17:05, Christoph Hellwig wrote:
>
> a) there is no multiath support for it, and we simply can't break existing
> setups that use.
> b) there is no support for I/O schedulers at all. This might be okay
> for virtio-scsi, where in general you have a host scheduler, but for
> real hardware that still has to deal with more spinning rust than
> solid state it's a blocker. Fortuntely Jens is working on that one.
It is sort-of okay for virtio-scsi (and virtio-blk). Deadline provides
a good speedup over noop for virtual disks, even in the presence of a
host scheduler---though nobody ever benchmarked why.
Paolo
prev parent reply other threads:[~2014-11-11 17:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-09 16:57 [PATCH 0/2] virtio_scsi: support multi hw queue of blk-mq Ming Lei
2014-11-09 16:57 ` [PATCH 1/2] scsi: introduce force_blk_mq Ming Lei
2014-11-09 16:57 ` [PATCH 2/2] virtio_scsi: support multi hw queue of blk-mq Ming Lei
2014-11-10 10:41 ` Paolo Bonzini
2014-11-10 13:39 ` Christoph Hellwig
2014-11-10 14:25 ` Ming Lei
2014-11-10 16:05 ` Christoph Hellwig
2014-11-11 17:09 ` Paolo Bonzini [this message]
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