From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, Wei Li <wei.d.li@oracle.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
Dongli Zhang <dongli.zhang@oracle.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Following up questions related to QEMU and I/O Thread
Date: Fri, 26 Apr 2019 10:14:16 +0200 [thread overview]
Message-ID: <44520476-d6a8-2e3f-1602-388e2e1e874e@redhat.com> (raw)
In-Reply-To: <20190423120453.GF32465@stefanha-x1.localdomain>
On 23/04/19 14:04, Stefan Hajnoczi wrote:
>> In addition, does Virtio-scsi support Batch I/O Submission feature
>> which may be able to increase the IOPS via reducing the number of
>> system calls?
>
> I don't see obvious batching support in drivers/scsi/virtio_scsi.c.
> The Linux block layer supports batching but I'm not sure if the SCSI
> layer does.
I think he's referring to QEMU, in which case yes, virtio-scsi does
batch I/O submission. See virtio_scsi_handle_cmd_req_prepare and
virtio_scsi_handle_cmd_req_submit in hw/scsi/virtio-scsi.c, they do
blk_io_plug and blk_io_unplug in order to batch I/O requests from QEMU
to the host kernel.
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, Wei Li <wei.d.li@oracle.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
qemu-devel@nongnu.org, Dongli Zhang <dongli.zhang@oracle.com>
Subject: Re: [Qemu-devel] Following up questions related to QEMU and I/O Thread
Date: Fri, 26 Apr 2019 10:14:16 +0200 [thread overview]
Message-ID: <44520476-d6a8-2e3f-1602-388e2e1e874e@redhat.com> (raw)
Message-ID: <20190426081416.xvonVrIGPfGEHf_7HQLqpTfxfq6hpYcUInbBq3LPw-o@z> (raw)
In-Reply-To: <20190423120453.GF32465@stefanha-x1.localdomain>
On 23/04/19 14:04, Stefan Hajnoczi wrote:
>> In addition, does Virtio-scsi support Batch I/O Submission feature
>> which may be able to increase the IOPS via reducing the number of
>> system calls?
>
> I don't see obvious batching support in drivers/scsi/virtio_scsi.c.
> The Linux block layer supports batching but I'm not sure if the SCSI
> layer does.
I think he's referring to QEMU, in which case yes, virtio-scsi does
batch I/O submission. See virtio_scsi_handle_cmd_req_prepare and
virtio_scsi_handle_cmd_req_submit in hw/scsi/virtio-scsi.c, they do
blk_io_plug and blk_io_unplug in order to batch I/O requests from QEMU
to the host kernel.
Paolo
next prev parent reply other threads:[~2019-04-26 8:14 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-04 17:33 [Qemu-devel] Following up questions related to QEMU and I/O Thread Wei Li
2019-03-05 17:29 ` Stefan Hajnoczi
[not found] ` <2D7F11D0-4A02-4A0F-961D-854240376B17@oracle.com>
2019-04-01 9:07 ` Stefan Hajnoczi
2019-04-05 21:09 ` Wei Li
2019-04-05 21:09 ` Wei Li
2019-04-16 14:01 ` Paolo Bonzini
2019-04-16 14:01 ` Paolo Bonzini
2019-04-17 1:38 ` Wei Li
2019-04-17 1:38 ` Wei Li
2019-04-17 12:17 ` Paolo Bonzini
2019-04-17 12:17 ` Paolo Bonzini
2019-04-18 3:34 ` Wei Li
2019-04-18 3:34 ` Wei Li
[not found] ` <CC372DF3-1AC6-46B5-98A5-21159497034A@oracle.com>
2019-04-15 17:34 ` Wei Li
2019-04-15 17:34 ` Wei Li
2019-04-15 23:23 ` Dongli Zhang
2019-04-15 23:23 ` Dongli Zhang
2019-04-16 9:20 ` Stefan Hajnoczi
2019-04-16 9:20 ` Stefan Hajnoczi
2019-04-17 1:42 ` Wei Li
2019-04-17 1:42 ` Wei Li
[not found] ` <8E5AF770-69ED-4D44-8A25-B51344996D9E@oracle.com>
2019-04-23 4:21 ` Wei Li
2019-04-23 4:21 ` Wei Li
2019-04-23 12:04 ` Stefan Hajnoczi
2019-04-23 12:04 ` Stefan Hajnoczi
2019-04-26 8:14 ` Paolo Bonzini [this message]
2019-04-26 8:14 ` Paolo Bonzini
2019-04-26 23:02 ` Wei Li
2019-04-26 23:02 ` Wei Li
2019-04-27 4:24 ` Paolo Bonzini
2019-04-27 4:24 ` Paolo Bonzini
2019-04-29 17:49 ` Wei Li
2019-04-29 17:49 ` Wei Li
2019-04-29 13:40 ` Stefan Hajnoczi
2019-04-29 13:40 ` Stefan Hajnoczi
2019-04-29 17:56 ` Wei Li
2019-04-29 17:56 ` Wei Li
2019-05-01 16:36 ` Stefan Hajnoczi
2019-05-01 16:36 ` Stefan Hajnoczi
2019-05-03 16:21 ` Wei Li
2019-05-03 16:21 ` Wei Li
2019-05-03 18:05 ` Paolo Bonzini
2019-05-03 18:05 ` Paolo Bonzini
2019-05-03 18:11 ` Wei Li
2019-05-03 18:11 ` Wei Li
2019-04-30 11:21 ` Paolo Bonzini
2019-04-30 11:21 ` Paolo Bonzini
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