linux-kernel - Re: [PATCH] clockevents: avoid unnecessary reprograming of event timer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <6cc912950902131050g7dcac4ablf2b9e997d3bef148@mail.gmail.com>
Date:	Fri, 13 Feb 2009 10:50:39 -0800
From:	Michael Davidson <md@...gle.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	mbligh@...gle.com, tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clockevents: avoid unnecessary reprograming of event 
	timer

On Fri, Feb 13, 2009 at 12:22 AM, Ingo Molnar <mingo@...e.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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/