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From: Ingo Molnar <mingo@elte.hu>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Rob van der Heij <rvdheij@gmail.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	john stultz <johnstul@us.ibm.com>,
	Andi Kleen <andi@firstfloor.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [patch 0/2] NOHZ vs. profile/oprofile v2
Date: Mon, 22 Jun 2009 17:05:53 +0200	[thread overview]
Message-ID: <20090622150553.GA14363@elte.hu> (raw)
In-Reply-To: <20090622165936.0bb776e1@skybase>


* Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:

> On Mon, 22 Jun 2009 16:41:10 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
> 
> > Hm, this is rather ugly. Why not use hrtimers like 'perf' does when 
> > it fallback-samples based on the timer tick?
> > 
> > That method has three advantages:
> > 
> >  - no weird hookery needed
> >  - resolution can go far beyond HZ
> >  - it is evidently dynticks-safe
> 
> Hmm, if we replace the HZ based oprofile tick with an hrtimer we 
> should add an interface to configure the sample interval as well, 
> no? Otherwise we just replace one timer event (HZ) with another 
> (hrtimer).

Even if the hrtimer is set with a 1/HZ period it's a better 
solution, as it's dynticks safe without invasive changes.

	Ingo

  reply	other threads:[~2009-06-22 15:06 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-03 15:22 [patch 0/2] NOHZ vs. profile/oprofile v2 Martin Schwidefsky
2009-06-03 15:22 ` [patch 1/2] idle profile hits with NOHZ Martin Schwidefsky
2009-06-03 15:22 ` [patch 2/2] keep on ticking if oprofile is active Martin Schwidefsky
2009-06-09 20:52 ` [patch 0/2] NOHZ vs. profile/oprofile v2 Thomas Gleixner
2009-06-10 17:33   ` Martin Schwidefsky
2009-06-22 14:26   ` Martin Schwidefsky
2009-06-22 14:41     ` Ingo Molnar
2009-06-22 14:59       ` Martin Schwidefsky
2009-06-22 15:05         ` Ingo Molnar [this message]
2009-06-22 15:18           ` Martin Schwidefsky
2009-06-22 15:29             ` Ingo Molnar
2009-06-22 15:36               ` Martin Schwidefsky
2009-06-22 15:40                 ` Ingo Molnar
2009-06-22 16:37                   ` Martin Schwidefsky
2009-06-24 16:51                   ` Martin Schwidefsky
2009-06-24 17:47                     ` Ingo Molnar
2010-03-02 13:57                     ` Aaro Koskinen
2010-03-02 15:01                       ` Martin Schwidefsky
2010-03-02 15:08                         ` Thomas Gleixner
2010-03-02 15:25                           ` Martin Schwidefsky
2010-03-02 15:38                           ` Robert Richter

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