Re: unusual scheduling performance

From: Martin J. Bligh (mbligh@aracnet.com)
Date: Mon Nov 18 2002 - 11:34:34 EST


> On 16x, 2.5.47 kernel compiles take about 26s when the machine is
> otherwise idle.
>
> On 32x, 2.5.47 kernel compiles take about 48s when the machine is
> otherwise idle.
>
> When a single-threaded task consumes an entire cpu, kernel compiles
> take 36s on 32s when the machine is idle aside from the task consuming
> that cpu and the kernel compile itself.
>
> I suspect the scheduler, because cpu reporting in top(1) shows that a
> two or more cpu-intensive tasks are concentrated on the same cpu, and
> some long-lived tasks appear to be "bouncing" across cpus. If someone
> with knowledge and/or expertise with respect to scheduling semantics
> could look into this, I would be much obliged. Resolving this would
> likely address many SMP and/or NUMA scheduling performance issues.

1. make -j <what?>

2. profiles?

3. Can you try the latest set of NUMA sched patches posted by Eric Focht?

M.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Nov 23 2002 - 22:00:23 EST