From: Keith Busch <kbusch@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Li Feng <fengli@smartx.com>, Jens Axboe <axboe@kernel.dk>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
"open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:VIRTIO BLOCK AND SCSI DRIVERS"
<virtualization@lists.linux.dev>
Subject: Re: [PATCH] virtio_blk: set the default scheduler to none
Date: Thu, 7 Dec 2023 19:44:37 -0700 [thread overview]
Message-ID: <ZXKDFdzXN4xQAuBm@kbusch-mbp> (raw)
In-Reply-To: <ZXJ4xNawrSRem2qe@fedora>
On Fri, Dec 08, 2023 at 10:00:36AM +0800, Ming Lei wrote:
> On Thu, Dec 07, 2023 at 12:31:05PM +0800, Li Feng wrote:
> > virtio-blk is generally used in cloud computing scenarios, where the
> > performance of virtual disks is very important. The mq-deadline scheduler
> > has a big performance drop compared to none with single queue. In my tests,
> > mq-deadline 4k readread iops were 270k compared to 450k for none. So here
> > the default scheduler of virtio-blk is set to "none".
>
> The test result shows you may not test HDD. backing of virtio-blk.
>
> none can lose IO merge capability more or less, so probably sequential IO perf
> drops in case of HDD backing.
More of a curiosity, as I don't immediately even have an HDD to test
with! Isn't it more useful for the host providing the backing HDD use an
appropriate IO scheduler? virtio-blk has similiarities with a stacking
block driver, and we usually don't need to stack IO schedulers.
next prev parent reply other threads:[~2023-12-08 2:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 4:31 [PATCH] virtio_blk: set the default scheduler to none Li Feng
2023-12-07 6:02 ` Jason Wang
2023-12-07 6:32 ` Li Feng
2023-12-07 6:38 ` Michael S. Tsirkin
2023-12-07 6:53 ` Chaitanya Kulkarni
2023-12-07 7:21 ` Li Feng
2023-12-07 9:48 ` Chaitanya Kulkarni
2023-12-07 14:51 ` Stefan Hajnoczi
2023-12-07 14:55 ` Paolo Bonzini
2023-12-07 15:19 ` Christoph Hellwig
2023-12-08 2:00 ` Ming Lei
2023-12-08 2:44 ` Keith Busch [this message]
2023-12-08 3:15 ` Jens Axboe
2023-12-08 3:54 ` Ming Lei
2023-12-08 5:55 ` Li Feng
2023-12-08 11:07 ` Paolo Bonzini
2023-12-25 14:20 ` Michael S. Tsirkin
2023-12-26 9:01 ` Li Feng
2023-12-26 9:05 ` Michael S. Tsirkin
2023-12-26 12:14 ` Li Feng
2023-12-26 15:38 ` Michael S. Tsirkin
2023-12-27 7:26 ` Li Feng
2023-12-27 10:06 ` Michael S. Tsirkin
2023-12-28 7:25 ` Li Feng
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