From: Peter Zijlstra <peterz@infradead.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: mingo@redhat.com, gleb@redhat.com, glommer@parallels.com,
tglx@linutronix.de, jeremy@goop.org, rostedt@goodmis.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] remove sched notifier for cross-cpu migrations
Date: Thu, 11 Jul 2013 11:52:49 +0200 [thread overview]
Message-ID: <20130711095249.GA25631@dyad.programming.kicks-ass.net> (raw)
In-Reply-To: <20130711012157.GA21489@amt.cnet>
On Wed, Jul 10, 2013 at 10:21:57PM -0300, Marcelo Tosatti wrote:
>
> Linux as a guest on KVM hypervisor, the only user of the pvclock
> vsyscall interface, does not require notification on task migration
> because:
>
> 1. cpu ID number maps 1:1 to per-CPU pvclock time info.
> 2. per-CPU pvclock time info is updated if the
> underlying CPU changes.
> 3. that version is increased whenever underlying CPU
> changes.
>
> Which is sufficient to guarantee nanoseconds counter
> is calculated properly.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Awesome, thanks!
Acked-by: Peter Zijlstra <peterz@infradead.org>
next prev parent reply other threads:[~2013-07-11 9:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-10 10:34 sched: add notifier for cross-cpu migrations Peter Zijlstra
2013-07-10 14:39 ` Ingo Molnar
2013-07-10 14:52 ` Peter Zijlstra
2013-07-11 1:21 ` [PATCH] remove sched " Marcelo Tosatti
2013-07-11 8:10 ` Gleb Natapov
2013-07-11 22:15 ` Marcelo Tosatti
2013-07-11 9:52 ` Peter Zijlstra [this message]
2013-07-14 11:16 ` Gleb Natapov
2013-08-23 10:22 ` Peter Zijlstra
2013-08-23 10:31 ` Gleb Natapov
2013-08-23 10:34 ` Peter Zijlstra
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