From: Dan Hecht <dhecht@vmware.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: dwalker@mvista.com, cpufreq@lists.linux.org.uk,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Con Kolivas <kernel@kolivas.org>,
Chris Wright <chrisw@sous-sol.org>,
Virtualization Mailing List <virtualization@lists.osdl.org>,
john stultz <johnstul@us.ibm.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
paulus@au.ibm.com, schwidefsky@de.ibm.com,
Rik van Riel <riel@redhat.com>, Zachary Amsden <zach@vmware.com>
Subject: Re: Stolen and degraded time and schedulers
Date: Thu, 15 Mar 2007 13:07:36 -0700 [thread overview]
Message-ID: <45F9A788.1010008@vmware.com> (raw)
In-Reply-To: <45F9A42D.7090205@goop.org>
On 03/15/2007 12:53 PM, Jeremy Fitzhardinge wrote:
> Dan Hecht wrote:
>> Available time is defined to be (real_time - stolen_time). i.e. time
>> in which the vcpu is either running or not ready to run [because it is
>> halted, and nothing is pending]).
>
> Hm, the Xen definition of stolen time is "time VCPU spent in runnable
> (vs running) or offline state". If the VCPU was blocked anyway, then
> its never considered to be stolen. Offline means the VCPU was paused by
> the administrator, or during suspend/resume.
>
>
Yes, the part in the "i.e." above is describing available time. So, it
is essentially is the same definition of stolen time VMI uses:
stolen time == ready to run but not running
available time == running or not ready to run
Basically, a vcpu starts off running (and this time is counted as
available time). Eventually, it will either be preempted by the
hypervisor and descheduled (then this time becomes stolen since the vcpu
is still ready), or it will decide to halt (then the time remains
accounted towards available time). Once the vcpu is halted, then
eventually something happens and we should deliver a virtual interrupt
to the vcpu. The time between that something happening (e.g. host I/O
completing, an alarm expiring) and the vcpu actually starting to run
again is accounted as stolen.
next prev parent reply other threads:[~2007-03-15 20:07 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-13 16:31 Stolen and degraded time and schedulers Jeremy Fitzhardinge
2007-03-13 20:12 ` john stultz
2007-03-13 20:32 ` Jeremy Fitzhardinge
2007-03-13 21:27 ` Daniel Walker
2007-03-13 21:59 ` Jeremy Fitzhardinge
2007-03-14 0:43 ` Dan Hecht
2007-03-14 4:37 ` Jeremy Fitzhardinge
2007-03-14 13:58 ` Lennart Sorensen
2007-03-14 15:08 ` Jeremy Fitzhardinge
2007-03-14 15:12 ` Lennart Sorensen
2007-03-14 19:02 ` Dan Hecht
2007-03-14 19:34 ` Jeremy Fitzhardinge
2007-03-14 19:45 ` Rik van Riel
2007-03-14 19:47 ` Jeremy Fitzhardinge
2007-03-14 20:02 ` Rik van Riel
2007-03-14 20:26 ` Dan Hecht
2007-03-14 20:31 ` Jeremy Fitzhardinge
2007-03-14 20:46 ` Dan Hecht
2007-03-14 21:18 ` Jeremy Fitzhardinge
2007-03-15 19:09 ` Dan Hecht
2007-03-15 19:18 ` Jeremy Fitzhardinge
2007-03-15 19:48 ` Rik van Riel
2007-03-15 19:53 ` Jeremy Fitzhardinge
2007-03-15 20:07 ` Dan Hecht [this message]
2007-03-15 20:14 ` Rik van Riel
2007-03-15 20:35 ` Dan Hecht
2007-03-16 8:59 ` Martin Schwidefsky
2007-03-14 20:38 ` Ingo Molnar
2007-03-14 20:59 ` Jeremy Fitzhardinge
2007-03-16 8:38 ` Ingo Molnar
2007-03-16 16:53 ` Jeremy Fitzhardinge
2007-03-15 5:23 ` Paul Mackerras
2007-03-15 19:33 ` Jeremy Fitzhardinge
2007-03-14 2:00 ` Daniel Walker
2007-03-14 6:52 ` Jeremy Fitzhardinge
2007-03-14 8:20 ` Zan Lynx
2007-03-14 16:11 ` Daniel Walker
2007-03-14 16:37 ` Jeremy Fitzhardinge
2007-03-14 16:59 ` Daniel Walker
2007-03-14 17:08 ` Jeremy Fitzhardinge
2007-03-14 18:06 ` Daniel Walker
2007-03-14 18:41 ` Jeremy Fitzhardinge
2007-03-14 19:00 ` Daniel Walker
2007-03-14 19:44 ` Jeremy Fitzhardinge
2007-03-14 20:33 ` Daniel Walker
2007-03-14 21:16 ` Jeremy Fitzhardinge
2007-03-14 21:34 ` Daniel Walker
2007-03-14 21:42 ` Jeremy Fitzhardinge
2007-03-14 21:36 ` Con Kolivas
2007-03-14 21:38 ` Jeremy Fitzhardinge
2007-03-14 21:40 ` Con Kolivas
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