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Date: Tue, 12 Oct 2004 11:17:40 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Lee Revell <rlrevell@joe-job.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, "K.R. Foley" <kr@cybsft.com>,
       Rui Nuno Capela <rncbc@rncbc.org>,
       Florian Schmidt <mista.tapas@gmx.net>, Mark_H_Johnson@raytheon.com,
       Fernando Pablo Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Subject: Re: [patch] voluntary-preempt-2.6.9-rc3-mm3-T3
Message-ID: <20041012091740.GA18736@elte.hu>
References: <20040922103340.GA9683@elte.hu> <20040923122838.GA9252@elte.hu> <20040923211206.GA2366@elte.hu> <20040924074416.GA17924@elte.hu> <20040928000516.GA3096@elte.hu> <20041003210926.GA1267@elte.hu> <20041004215315.GA17707@elte.hu> <20041005134707.GA32033@elte.hu> <20041007105230.GA17411@elte.hu> <1097555404.1553.18.camel@krustophenia.net>
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* Lee Revell <rlrevell@joe-job.com> wrote:

> Just to recap, these are the three problem areas that still produce
> latencies over 500 usec on my machine.
> 
> 	journal_clean_checkpoint_list

you might want to send this trace to Andrew too - the primary master of
ext3 latency-breaking.

> 	rt_garbage_collect

this one is still nasty and needs revisiting.

> 	vga console
> 
> I have found that the latter does not require switching back and forth
> to X; anything that produces a lot of console output can trigger 500
> usec latencies.

the vga console one we got rid of at a certain stage and it now
resurfaced. The issue was doing VGA-text-RAM copies/memsets under the
vga_lock. Maybe there were changes in vgacon recently that moved some of
those back under the lock?

	Ingo