[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20070710210945.GA4231@elte.hu>
Date: Tue, 10 Jul 2007 23:09:45 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Martin Bligh <mbligh@...igh.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Andy Whitcroft <apw@...dowen.org>
Subject: Re: Performance regression in 2.6.22-git1 (new sched code?)
* Martin Bligh <mbligh@...igh.org> wrote:
> ~ 1% on 4-way x86_64
>
> http://test.kernel.org/perf/kernbench.elm3b6.png
>
> ~ 4% on 16-way NUMA-Q (i386)
>
> http://test.kernel.org/perf/kernbench.moe.png
>
> ~ 1.5% on 4-way i386
>
> http://test.kernel.org/perf/kernbench.elm3b132.png
thx! I'll check this tomorrow, meanwhile here are a few quick ideas.
1) does reverting this patch improve performance:
commit 9c4801cebc2add1fe514bc8eb201b16372eee11a
Author: Ingo Molnar <mingo@...e.hu>
Date: Mon Jul 9 18:52:01 2007 +0200
sched: more agressive idle balancing
2) does changing CONFIG_HZ=250 to CONFIG_HZ=100 improve the numbers?
CFS has some internal tuning that depends on HZ - a higher HZ is a
sign that the user wants more finegrained scheduling. So for maximum
server throughput, use CONFIG_HZ=100.
3) could you turn off CONFIG_SCHED_DEBUG? The cost is small but perhaps
measurable.
(these 3 suggestions could be tested together - they should have
cumulative effects.)
Ingo
-
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/
Powered by blists - more mailing lists