From: Avi Kivity <avi@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Ingo Molnar <mingo@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <ak@linux.intel.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH RFC] sched: add notifier for process migration
Date: Sat, 10 Oct 2009 11:05:20 +0200 [thread overview]
Message-ID: <4AD04E50.7060001@redhat.com> (raw)
In-Reply-To: <1255158863.7866.25.camel@twins>
On 10/10/2009 09:14 AM, Peter Zijlstra wrote:
> Why not do something like:
>
> struct {
> u64 tsc;
> u32 aux;
> } tscp = rdtscp();
>
> local_time_info = timeinfo[tscp_cpu(tscp)];
>
> /* yay, consistent tsc and timeinfo !! */
>
First, not all processors support rdtscp. Second, timeinfo might change
at any time due to cpu frequency changes or the entire cpu being
migrated, so we need to loop in any case.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2009-10-10 9:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-09 21:01 [PATCH RFC] sched: add notifier for process migration Jeremy Fitzhardinge
2009-10-09 22:02 ` Peter Zijlstra
2009-10-09 22:43 ` Jeremy Fitzhardinge
2009-10-10 7:14 ` Peter Zijlstra
2009-10-10 9:05 ` Avi Kivity [this message]
2009-10-10 9:24 ` Peter Zijlstra
2009-10-10 9:36 ` Jeremy Fitzhardinge
2009-10-10 10:12 ` Peter Zijlstra
2009-10-13 21:25 ` Jeremy Fitzhardinge
2009-10-14 7:05 ` Ingo Molnar
2009-10-14 9:26 ` Peter Zijlstra
2009-10-14 10:37 ` Avi Kivity
2009-10-14 14:41 ` Jason Baron
2009-10-14 16:15 ` Jeremy Fitzhardinge
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