From: Michael Davidson <md@google.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: mbligh@google.com, tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] clockevents: avoid unnecessary reprograming of event timer
Date: Fri, 13 Feb 2009 10:50:39 -0800 [thread overview]
Message-ID: <6cc912950902131050g7dcac4ablf2b9e997d3bef148@mail.gmail.com> (raw)
In-Reply-To: <20090213082223.GA4606@elte.hu>
On Fri, Feb 13, 2009 at 12:22 AM, Ingo Molnar <mingo@elte.hu> wrote:
>
> Hm, given that a good high-res source has nanoseconds resolution,
> what's the chance of this optimization triggering in practice?
> Near zero i think - unless we trigger useless reprogramming without
> having added or removed any new timers - but then we should
> concentrate on analyzing the reason for that redundant reprogramming.
>
> Does it trigger often for you?
Yes - running 2.6.26 built with CONFIG_NO_HZ on a 4 core AMD system,
depending on the workload I see it trigger between 40 and 100 times a second.
I will take a closer look at why this is happening.
md
prev parent reply other threads:[~2009-02-13 18:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-12 22:23 Michael Davidson
2009-02-13 8:22 ` Ingo Molnar
2009-02-13 9:39 ` Thomas Gleixner
2009-02-13 9:55 ` Ingo Molnar
2009-02-13 18:50 ` Michael Davidson [this message]
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