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From: Christoph Hellwig <hch@lst.de>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Christoph Hellwig <hch@lst.de>, Avi Kivity <avi@redhat.com>,
	Matthew Tippett <tippettm@gmail.com>,
	Dustin Kirkland <dustin.kirkland@gmail.com>, RW <kvm@tauceti.net>,
	kvm@vger.kernel.org
Subject: Re: sync guest calls made async on host - SQLite performance
Date: Thu, 15 Oct 2009 14:17:02 +0200	[thread overview]
Message-ID: <20091015121702.GA3780@lst.de> (raw)
In-Reply-To: <4AD6569F.80803@codemonkey.ws>

On Wed, Oct 14, 2009 at 05:54:23PM -0500, Anthony Liguori wrote:
> >Historically it didn't and the only safe way to use virtio was in
> >cache=writethrough mode.
> 
> Which should be the default on Ubuntu's kvm that this report is 
> concerned with so I'm a bit confused.

So can we please get the detailed setup where this happens, that is:

filesystem used in the guest
any volume manager / software raid used in the guest
kernel version in the guest
image format used
qemu command line including caching mode, using ide/scsi/virtio, etc
qemu/kvm version
filesystem used in the host
any volume manager / software raid used in the host
kernel version in the host


> Avi's patch is a performance optimization, not a correctness issue?

It could actually minimally degrade performace.  For the existing
filesystems as upper layer it doesn not improve correctness either.


  parent reply	other threads:[~2009-10-15 12:17 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-25  7:00 sync guest calls made async on host - SQLite performance RW
2009-09-27 11:37 ` Avi Kivity
2009-09-27 12:07   ` Matthew Tippett
2009-09-29 19:02     ` Anthony Liguori
2009-09-29 19:32       ` Matthew Tippett
2009-09-29 20:46         ` Dustin Kirkland
2009-09-29 20:51         ` Anthony Liguori
2009-10-07 14:15           ` Matthew Tippett
2009-10-07 16:53           ` Matthew Tippett
2009-10-07 18:59             ` Dustin Kirkland
2009-10-07 19:31               ` Matthew Tippett
2009-10-07 20:12                 ` Avi Kivity
2009-10-07 21:01                   ` Matthew Tippett
2009-10-09  6:05                 ` Dustin Kirkland
     [not found]                 ` <4ACE0196.9010904@gmail.com>
     [not found]                   ` <d9c105ea0910082312n7218e1abhc69a2be660838e89@mail.gmail.com>
     [not found]                     ` <f28b49ce0910090425p385636c3he6dfb7595927d7e4@mail.gmail.com>
2009-10-09 15:18                       ` Dustin Kirkland
2009-10-09 19:06                         ` Matthew Tippett
2009-10-11  9:16                           ` Avi Kivity
2009-10-13 22:37                             ` Christoph Hellwig
2009-10-14 11:03                               ` Avi Kivity
2009-10-14 12:03                                 ` [PATCH] virtio-blk: fallback to draining the queue if barrier ops are not supported Avi Kivity
2009-10-14 14:46                                   ` Javier Guerra
2009-10-14 16:53                                     ` Avi Kivity
2009-10-14 15:38                                   ` Michael Tokarev
2009-10-14 15:46                                     ` Christoph Hellwig
2009-10-14 13:41                                 ` sync guest calls made async on host - SQLite performance Christoph Hellwig
2009-10-14 16:56                                   ` Avi Kivity
2009-10-14 17:02                                     ` Christoph Hellwig
2009-10-14 22:54                                       ` Anthony Liguori
2009-10-14 23:37                                         ` Avi Kivity
2009-10-15 12:17                                         ` Christoph Hellwig [this message]
2009-10-15 12:36                                           ` Christoph Hellwig
2009-10-19  5:56                                           ` Avi Kivity
2009-10-13 23:08                           ` Anthony Liguori
2009-10-14  2:09                             ` Matthew Tippett
2009-10-14  4:12                               ` Dustin Kirkland
2009-10-14 11:32                                 ` Matthew Tippett
  -- strict thread matches above, loose matches on Subject: below --
2009-09-25  2:11 Ian Woodstock
2009-09-25  3:13 ` Matthew Tippett
2009-09-23 15:58 Matthew Tippett
2009-09-24 11:44 ` Avi Kivity
2009-09-24 12:31   ` Matthew Tippett
2009-09-24 13:03     ` Avi Kivity
2009-09-24 19:49       ` Matthew Tippett
2009-09-25  7:22         ` Avi Kivity
2009-09-25 11:33           ` Matthew Tippett
2009-09-25 15:04             ` Avi Kivity
2009-09-29 18:58             ` Anthony Liguori
2009-09-29 18:57           ` Anthony Liguori
2009-09-29 18:54 ` Anthony Liguori

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