Re: [patch 00/21] high resolution timers / dynamic ticks - V2

From: Thomas Gleixner
Date: Mon Oct 02 2006 - 09:41:31 EST


On Mon, 2006-10-02 at 09:02 -0400, Valdis.Kletnieks@xxxxxx wrote:
> On Sun, 01 Oct 2006 22:59:01 -0000, Thomas Gleixner said:
> > the following patch series is an update in response to your review.
>
> First runtime results - no lockups or other severe badness in a half-hour or so
> of running.
>
> -mm2-hrt-dynticks5 shows severe clock drift issues if you run 'cpuspeed'.
>
> Using speedstep-ich as a kernel built-in, and cpuspeed is invoked as:
>
> cpuspeed -d -n -i 10 -p 10 50 -a /proc/acpi/ac_adapter/*/state
>
> If cpuspeed drops the CPU speed from the default 1.6Ghz down to 1.2Ghz (the
> only 2 speeds available on this core), the system clock proceeds to lose
> about 15 seconds a minute. I haven't dug further into why yet. (If the system
> is busy so cpuspeed keeps the processor at 1.6Ghz, the clock doesn't drift
> as much - so it looks like a "when speed is 1.2Ghz" issue...)

Can you please send me the bootlog and further dmesg output (especially
when related to timers / cpufreq).

> I'm also seeing gkrellm reporting about 25% CPU use when "near-idle" (X is up
> but not much is going on) when that's usually down around 5-6%. I need to
> collect some oprofile numbers and investigate that as well.

I look into the accounting fixups again.

tglx




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