All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stefan Hajnoczi <stefanha@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	Stefan Hajnoczi <stefanha@gmail.com>,
	qemu-devel@nongnu.org, famz@redhat.com, qemu-block@nongnu.org
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH v4 8/8] linux-aio: share one LinuxAioState within an AioContext
Date: Wed, 11 May 2016 14:22:11 +0100	[thread overview]
Message-ID: <20160511132211.GB25461@stefanha-x1.localdomain> (raw)
In-Reply-To: <5731B8BB.3020600@redhat.com>

[-- Attachment #1: Type: text/plain, Size: 870 bytes --]

On Tue, May 10, 2016 at 12:32:27PM +0200, Paolo Bonzini wrote:
> On 10/05/2016 11:40, Kevin Wolf wrote:
> > > Regarding performance, I'm thinking about a guest with 8 disks (queue
> > > depth 32).  The worst case is when the guest submits 32 requests at once
> > > but the Linux AIO event limit has already been reached.  Then the disk
> > > is starved until other disks' requests complete.
> >
> > Sounds like a valid concern.
> 
> Oh, so you're concerned about the non-dataplane case.  My suspicion is
> that, with such a number of outstanding I/O, you probably have bad
> performance unless you use dataplane.
> 
> Also, aio=threads has had a 64 I/O limit for years and we've never heard
> about problems with stuck I/O.  But I agree that it's one area to keep
> an eye on.

Good point.  In that case I don't feel so bad if we merge this.

Stefan

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

  reply	other threads:[~2016-05-11 13:22 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-07 16:33 [Qemu-devel] [PATCH v4 0/8] bdrv_flush_io_queue removal, shared LinuxAioState Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 1/8] block: Don't disable I/O throttling on sync requests Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 2/8] block: make bdrv_start_throttled_reqs return void Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 3/8] block: move restarting of throttled reqs to block/throttle-groups.c Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 4/8] block: extract bdrv_drain_poll/bdrv_co_yield_to_drain from bdrv_drain/bdrv_co_drain Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 5/8] block: introduce bdrv_no_throttling_begin/end Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 6/8] block: plug whole tree at once, introduce bdrv_io_unplugged_begin/end Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 7/8] linux-aio: make it more type safe Paolo Bonzini
2016-04-07 16:33 ` [Qemu-devel] [PATCH v4 8/8] linux-aio: share one LinuxAioState within an AioContext Paolo Bonzini
2016-04-19  9:09   ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2016-05-09 16:31     ` Paolo Bonzini
2016-05-10  9:30       ` Stefan Hajnoczi
2016-05-10  9:40         ` Kevin Wolf
2016-05-10 10:32           ` Paolo Bonzini
2016-05-11 13:22             ` Stefan Hajnoczi [this message]
2016-05-11 13:18           ` Stefan Hajnoczi
2016-05-11 13:23   ` [Qemu-devel] " Stefan Hajnoczi
2016-04-19  9:10 ` [Qemu-devel] [Qemu-block] [PATCH v4 0/8] bdrv_flush_io_queue removal, shared LinuxAioState Stefan Hajnoczi
2016-04-19 15:09   ` Kevin Wolf

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160511132211.GB25461@stefanha-x1.localdomain \
    --to=stefanha@redhat.com \
    --cc=famz@redhat.com \
    --cc=kwolf@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-block@nongnu.org \
    --cc=qemu-devel@nongnu.org \
    --cc=stefanha@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.