Re: aim7 -30% regression in 2.6.24-rc1

From: Ingo Molnar
Date: Thu Nov 01 2007 - 04:58:48 EST



* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> static int one_hundred = 100;
> +static int int_max = INT_MAX;
>
> /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
> static int maxolduid = 65535;
> @@ -239,7 +240,10 @@ static struct ctl_table kern_table[] = {
> .data = &sysctl_sched_nr_latency,
> .maxlen = sizeof(unsigned int),
> .mode = 0644,
> - .proc_handler = &proc_dointvec,
> + .proc_handler = &proc_dointvec_minmax,
> + .strategy = &sysctl_intvec,
> + .extra1 = &one,
> + .extra2 = &int_max,

could we instead justmake sched_nr_latency non-tunable, and recalculate
it from the sysctl handler whenever sched_latency or
sched_min_granularity changes? That would avoid not only the division by
zero bug but also other out-of-spec tunings.

Ingo
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