From: Rik van Riel <riel@redhat.com>
To: lwcheng@cs.hku.hk
Cc: Glauber Costa <glommer@gmail.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] Paravirtual time accounting / IRQ time accounting
Date: Sat, 22 Mar 2014 10:57:28 -0400 [thread overview]
Message-ID: <532DA4D8.60102@redhat.com> (raw)
In-Reply-To: <20140322151540.9740576amzy5tdwk@intranet.cs.hku.hk>
On 03/22/2014 03:15 AM, lwcheng@cs.hku.hk wrote:
> I observe that sometimes irq_time only includes "part" of steal_time.
>
> Like you said, irq_time is in dozens-of-microseconds. In VMs, as all
> devices seen are virtual ones, irq_time seems to be not as desired
> as it is in physical hosts.
>
> A quick (but not radical) solution may be:
> disable CONFIG_IRQ_TIME_ACCOUNTING if CONFIG_PARAVIRT is selected.
> Just adopt tick-based accounting: CONFIG_TICK_CPU_ACCOUNTING
>
> I am thinking what irq_time really *means* in VMs.
That is not really an option for Linux distributions, which tend
to run the same kernel image on the host and in the guest...
--
All rights reversed
prev parent reply other threads:[~2014-03-22 14:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 9:42 [BUG] Paravirtual time accounting / IRQ time accounting lwcheng
2014-03-20 15:01 ` Glauber Costa
2014-03-21 5:50 ` Mike Galbraith
2014-03-22 6:47 ` lwcheng
2014-03-22 7:44 ` Mike Galbraith
2014-03-21 11:31 ` Rik van Riel
2014-03-22 7:15 ` lwcheng
2014-03-22 14:57 ` Rik van Riel [this message]
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