From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
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 11:24:22 +0200 [thread overview]
Message-ID: <1255166662.7866.28.camel@twins> (raw)
In-Reply-To: <4AD04E50.7060001@redhat.com>
On Sat, 2009-10-10 at 11:05 +0200, Avi Kivity wrote:
> 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.
Is that a real issue? If its not supported by the early hardware virt
chips, tough luck, they sucked anyway :-)
> 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.
Sure.
next prev parent reply other threads:[~2009-10-10 9:25 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
2009-10-10 9:24 ` Peter Zijlstra [this message]
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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