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From: Chris Friesen <chris.friesen@windriver.com>
To: "Benoît Canet" <benoit.canet@irqsave.net>,
	"Paolo Bonzini" <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] is there a limit on the number of in-flight I/O operations?
Date: Mon, 21 Jul 2014 08:59:45 -0600	[thread overview]
Message-ID: <53CD2AE1.6080803@windriver.com> (raw)
In-Reply-To: <20140719084537.GA3058@irqsave.net>

On 07/19/2014 02:45 AM, Benoît Canet wrote:

> I think in the throttling case the number of in flight operation is limited by
> the emulated hardware queue. Else request would pile up and throttling would be
> inefective.
>
> So this number should be around: #define VIRTIO_PCI_QUEUE_MAX 64 or something like than that.

Okay, that makes sense.  Do you know how much data can be written as 
part of a single operation?  We're using 2MB hugepages for the guest 
memory, and we saw the qemu RSS numbers jump from 25-30MB during normal 
operation up to 120-180MB when running dbench.  I'd like to know what 
the worst-case would be.

Thanks,
Chris

  reply	other threads:[~2014-07-21 15:00 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-18 14:58 [Qemu-devel] is there a limit on the number of in-flight I/O operations? Chris Friesen
2014-07-18 15:24 ` Paolo Bonzini
2014-07-18 16:22   ` Chris Friesen
2014-07-18 20:13     ` Paolo Bonzini
2014-07-18 22:48       ` Chris Friesen
2014-07-19  5:49         ` Paolo Bonzini
2014-07-19  6:27           ` Chris Friesen
2014-07-19  7:23             ` Paolo Bonzini
2014-07-19  8:45               ` Benoît Canet
2014-07-21 14:59                 ` Chris Friesen [this message]
2014-07-21 15:15                   ` Benoît Canet
2014-07-21 15:35                     ` Chris Friesen
2014-07-21 15:54                       ` Benoît Canet
2014-07-21 16:10                       ` Benoît Canet
2014-08-23  0:59                         ` Chris Friesen
2014-08-23  7:56                           ` Benoît Canet
2014-08-25 15:12                             ` Chris Friesen
2014-08-25 17:43                               ` Chris Friesen
2015-08-27 16:37                                 ` Stefan Hajnoczi
2015-08-27 16:33                               ` Stefan Hajnoczi
2014-08-25 21:50                             ` Chris Friesen
2014-08-27  5:43                               ` Chris Friesen
2015-05-14 13:42                                 ` Andrey Korolyov
2015-08-26 17:10                                   ` Andrey Korolyov
2015-08-26 23:31                                     ` Josh Durgin
2015-08-26 23:47                                       ` Andrey Korolyov
2015-08-27  0:56                                         ` Josh Durgin
2015-08-27 16:48                               ` Stefan Hajnoczi
2015-08-27 17:05                                 ` Stefan Hajnoczi
2015-08-27 16:49                               ` Stefan Hajnoczi
2015-08-28  0:31                                 ` Josh Durgin
2015-08-28  8:31                                   ` Andrey Korolyov
2014-07-21 19:47                       ` Benoît Canet
2014-07-21 21:12                         ` Chris Friesen
2014-07-21 22:04                           ` Benoît Canet
2014-07-18 15:54 ` Andrey Korolyov
2014-07-18 16:26   ` Chris Friesen
2014-07-18 16:30     ` Andrey Korolyov
2014-07-18 16:46       ` Chris Friesen
     [not found] <1000957815.25879188.1441820902018.JavaMail.zimbra@redhat.com>
2015-09-09 18:51 ` Jason Dillaman

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