From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: RE: rdtsc strangeness on upstream kernel
Date: Mon, 19 Jul 2010 17:34:16 -0700 [thread overview]
Message-ID: <4C44EF08.3070103@goop.org> (raw)
In-Reply-To: <681683ff-677b-4709-911e-3d90d7dbed7c@default>
On 07/19/2010 04:55 PM, Dan Magenheimer wrote:
>> With vcpus=2, timer0 goes up to about 2000 irq/sec on CPU0
>> and timer1 on CPU1 is the same while rdtsc/sec is about 20000.
>>
> No, wait, correct that...timer0 and timer1 are 1000 irq/sec.
> (I was using "watch -d" which defaults to updating every
> two seconds, not every second.)
>
>
>> Is it possible that the timer interrupt is using rdtsc
>> five times each interrupt?
>>
> TEN times each interrupt.
>
Do you have any other debugging/tracing enabled? CONFIG_XEN_DEBUG_FS
for example?
10 sounds a little high, but not necessarily completely unreasonable,
especially if there's tracing/debugging on.
J
next prev parent reply other threads:[~2010-07-20 0:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-19 23:19 rdtsc strangeness on upstream kernel Dan Magenheimer
2010-07-19 23:34 ` Jeremy Fitzhardinge
2010-07-19 23:51 ` Dan Magenheimer
[not found] ` <681683ff-677b-4709-911e-3d90d7dbed7c@default4C44EF08.3070103@goop.org>
2010-07-19 23:55 ` Dan Magenheimer
2010-07-20 0:34 ` Jeremy Fitzhardinge [this message]
2010-07-20 0:42 ` Dan Magenheimer
2010-07-20 0:44 ` Jeremy Fitzhardinge
2010-07-23 16:47 ` Dan Magenheimer
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