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From: Ingo Molnar <mingo@elte.hu>
To: linux-kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Sami Farin <7atbggg02@sneakemail.com>
Subject: Re: Linux 2.6.9 latencies: scheduler bug?
Date: Mon, 25 Oct 2004 14:58:07 +0200	[thread overview]
Message-ID: <20041025125807.GA8432@elte.hu> (raw)
In-Reply-To: <20041025120021.GA9917@m.safari.iki.fi>


* Sami Farin <7atbggg02@sneakemail.com> wrote:

> forget this stupid ip_tables.c patch, latencies have nothing to do with
> netfilter code, but bad interaction between xmms, rtc_latencytest
> and iptables.  I now get at max 3.1s (yup, 3100000us) latencies.
> http://safari.iki.fi/2.6.9-xmms-fun-1.png
> if you want to reproduce this:
> 1) run "rtc_latencytest 1024" (can't reproduce with "rtc_latencytest 512")
> 2) press play in xmms
> 3) start iptables-script

to further debug any latencies please apply the -RT patchset and enable
PREEMPT_TIMING (and LATENCY_TRACING), that enables us to tell us more
about the latencies. You dont have to enable PREEMPT_REALTIME (the most
experimental feature of the patchset) to measure latencies.

	Ingo

  parent reply	other threads:[~2004-10-25 12:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-24 21:26 Linux 2.6.9 latencies: 253ms in ip_tables.c:copy_entries_to_user(), 200ms in reiserfs/bitmap.c:scan_bitmap_block(), 4ms in i2c-algo-bit.c:bit_xfer() Sami Farin
2004-10-25 12:00 ` Linux 2.6.9 latencies: scheduler bug? Sami Farin
2004-10-25 12:43   ` Nick Piggin
2004-10-25 12:53     ` Sami Farin
2004-10-25 12:58   ` Ingo Molnar [this message]
2004-10-25 13:11     ` Sami Farin

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