From: Yong Zhang <yong.zhang0@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Venki Pallipadi <venki@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Aaron Durbin <adurbin@google.com>, Paul Turner <pjt@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1
Date: Mon, 27 Feb 2012 17:51:00 +0800 [thread overview]
Message-ID: <20120227095100.GC1112@zhy> (raw)
In-Reply-To: <1330335058.11248.37.camel@twins>
On Mon, Feb 27, 2012 at 10:30:58AM +0100, Peter Zijlstra wrote:
> On Mon, 2012-02-27 at 17:08 +0800, Yong Zhang wrote:
> > On Mon, Feb 27, 2012 at 09:38:01AM +0100, Peter Zijlstra wrote:
> > > On Fri, 2012-02-24 at 14:13 +0800, Yong Zhang wrote:
> > >
> > > > This remind me that we should have moved the irq_enter()/irq_exit() to
> > > > each arch's related irq handler.
> > > > see: http://marc.info/?l=linux-kernel&m=130709505700821&w=2
> > > >
> > > > So Peter, is there someone alread on it? or it still worth doing now?
> > >
> > > trouble was that some people didn't feel comfortable adding that
> > > overhead to plain resched IPIs that didn't need to do anything.
> >
> > Any ideas on where the plain resched IPIs come from?
>
> remote wakeups that don't queue I guess.
>
> IIRC I looked at it a while back and while not in the majority there
> were still a few (I only added counters, didn't look where they came
> from).
>
> However since 518cd623 there'd be a lot more I guess..
>
> Feel free to investigate. Also, some non-sched users of the resched ipi
> exist, eg. KVM uses it to kick a remote vcpu out from guest mode.
Thanks for the detail.
Will try to find if there is something interesting.
Thanks,
Yong
next prev parent reply other threads:[~2012-02-27 9:51 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-23 0:36 [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1 Venkatesh Pallipadi
2012-02-23 7:50 ` Ingo Molnar
2012-02-23 9:08 ` Peter Zijlstra
2012-02-23 20:04 ` Venki Pallipadi
2012-02-23 20:03 ` Venki Pallipadi
2012-03-02 0:33 ` Venki Pallipadi
2012-03-02 1:28 ` Suresh Siddha
2012-03-02 1:35 ` Venki Pallipadi
2012-03-02 1:37 ` Suresh Siddha
2012-03-02 2:00 ` Venki Pallipadi
2012-03-02 7:21 ` Ingo Molnar
2012-03-02 17:41 ` Suresh Siddha
2012-03-06 21:41 ` fork_idle from wq cleanup Venkatesh Pallipadi
2012-03-06 21:41 ` [PATCH 1/5] x86: Move fork_idle from wq and idle caching to common code Venkatesh Pallipadi
2012-03-06 21:41 ` [PATCH 2/5] ia64: Use common fork_idle_from_wq in smpboot Venkatesh Pallipadi
2012-03-06 21:41 ` [PATCH 3/5] mips: " Venkatesh Pallipadi
2012-03-06 22:51 ` Ralf Baechle
2012-03-06 21:41 ` [PATCH 4/5] powerpc: " Venkatesh Pallipadi
2012-03-06 21:41 ` [PATCH 5/5] s390: " Venkatesh Pallipadi
2012-03-07 7:00 ` Heiko Carstens
2012-03-07 6:06 ` fork_idle from wq cleanup Suresh Siddha
2012-02-23 9:30 ` [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1 Peter Zijlstra
2012-02-23 19:34 ` Venki Pallipadi
2012-02-24 5:41 ` Yong Zhang
2012-02-24 6:13 ` Yong Zhang
2012-02-27 8:38 ` Peter Zijlstra
2012-02-27 9:08 ` Yong Zhang
2012-02-27 9:30 ` Peter Zijlstra
2012-02-27 9:51 ` Yong Zhang [this message]
2012-02-26 1:32 ` Paul E. McKenney
2012-02-27 9:06 ` Yong Zhang
2012-02-27 17:05 ` Paul E. McKenney
2012-02-28 7:12 ` Yong Zhang
2012-02-28 13:05 ` Paul E. McKenney
2012-02-29 6:36 ` Yong Zhang
2012-02-27 8:45 ` Peter Zijlstra
2012-02-27 18:17 ` Venki Pallipadi
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