From: Rik van Riel <riel@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Glauber Costa <glommer@redhat.com>,
kvm@vger.kernel.org, avi@redhat.com, zamsden@redhat.com,
mtosatti@redhat.com, mingo@elte.hu
Subject: Re: [RFC v2 4/7] change kernel accounting to include steal time
Date: Mon, 30 Aug 2010 15:45:27 -0400 [thread overview]
Message-ID: <4C7C0A57.2010906@redhat.com> (raw)
In-Reply-To: <1283196005.1820.1340.camel@laptop>
On 08/30/2010 03:20 PM, Peter Zijlstra wrote:
> On Mon, 2010-08-30 at 15:17 -0400, Rik van Riel wrote:
>>
>> When time is accounted as steal time, it is NOT accounted as
>> to the current process user/system/..., which in turn should
>> help it in the scheduler.
>>
>> Am I overlooking something?
>
> Yeah, the scheduler doesn't care about the user/system time accounting
> at all... :-)
Uh oh. This would seem like something we'll want to fix
in an architecture independent way, so s390, etc. also
benefit from it.
I can see this being a real problem when the host and guest
OS have the same time slice - which is quite possible since
they may both be the same version of Linux.
Guest 1, alternating between processes A and B, may end up
with process A getting a lot of actual CPU time, and process
B being scheduled in when the VCPU itself is not running...
--
All rights reversed
next prev parent reply other threads:[~2010-08-30 19:45 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-30 16:06 [RFC v2 0/7] kvm stael time implementation Glauber Costa
2010-08-30 16:06 ` [RFC v2 1/7] change headers preparing for steal time Glauber Costa
2010-08-30 16:06 ` [RFC 1/8] Implement getnsboottime kernel API Glauber Costa
2010-08-30 16:06 ` [RFC v2 2/7] always call kvm_write_guest Glauber Costa
2010-08-30 16:06 ` [RFC 2/8] change headers preparing for steal time Glauber Costa
2010-08-30 16:06 ` [RFC 3/8] always call kvm_write_guest Glauber Costa
2010-08-30 16:06 ` [RFC v2 3/7] measure time out of guest Glauber Costa
2010-08-30 16:06 ` [RFC v2 4/7] change kernel accounting to include steal time Glauber Costa
2010-08-30 16:06 ` [RFC 4/8] measure time out of guest Glauber Costa
2010-08-30 16:06 ` [RFC 5/8] change kernel accounting to include steal time Glauber Costa
2010-08-30 16:06 ` [RFC v2 5/7] kvm steal time implementation Glauber Costa
2010-08-30 16:06 ` [RFC 6/8] " Glauber Costa
2010-08-30 16:06 ` [RFC v2 6/7] touch softlockup watchdog Glauber Costa
2010-08-30 16:06 ` [RFC v2 7/7] tell guest about steal time feature Glauber Costa
2010-08-30 16:06 ` [RFC 7/8] touch softlockup watchdog Glauber Costa
2010-08-30 16:06 ` [RFC 8/8] tell guest about steal time feature Glauber Costa
2010-08-30 17:33 ` [RFC v2 6/7] touch softlockup watchdog Jeremy Fitzhardinge
2010-08-30 18:07 ` Glauber Costa
2010-08-30 16:46 ` [RFC 5/8] change kernel accounting to include steal time Peter Zijlstra
2010-08-30 17:26 ` Glauber Costa
2010-08-30 17:30 ` [RFC v2 4/7] " Jeremy Fitzhardinge
2010-08-30 18:39 ` Rik van Riel
2010-08-30 19:07 ` Jeremy Fitzhardinge
2010-08-30 19:14 ` Peter Zijlstra
2010-08-30 19:17 ` Rik van Riel
2010-08-30 19:20 ` Peter Zijlstra
2010-08-30 19:45 ` Rik van Riel [this message]
2010-08-30 22:56 ` Jeremy Fitzhardinge
2010-08-30 23:03 ` Rik van Riel
2010-08-31 8:11 ` Peter Zijlstra
2010-09-02 18:19 ` Glauber Costa
2010-09-03 3:24 ` Jeremy Fitzhardinge
2010-09-03 7:18 ` Peter Zijlstra
2010-09-01 23:56 ` [RFC 1/8] Implement getnsboottime kernel API Zachary Amsden
2010-08-30 16:37 ` [RFC v2 0/7] kvm stael time implementation Peter Zijlstra
2010-08-30 16:45 ` Jeremy Fitzhardinge
2010-08-30 17:21 ` Glauber Costa
2010-08-30 17:20 ` Jeremy Fitzhardinge
2010-08-30 17:06 [RFC v2 0/7] kvm steal time implementation proposal Glauber Costa
2010-08-30 17:06 ` [RFC v2 4/7] change kernel accounting to include steal time Glauber Costa
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