From: Andrea Arcangeli <andrea@novell.com>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
Robert Love <rml@novell.com>, Roland Dreier <roland@topspin.com>,
linux-kernel@vger.kernel.org
Subject: Re: Preempt? (was Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA))
Date: Wed, 6 Oct 2004 06:03:23 +0200 [thread overview]
Message-ID: <20041006040323.GL26820@dualathlon.random> (raw)
In-Reply-To: <4163660A.4010804@pobox.com>
On Tue, Oct 05, 2004 at 11:27:06PM -0400, Jeff Garzik wrote:
> You're ignoring the argument :)
>
> If users and developers are presented with the _impression_ that long
> latency code paths don't exist, then nobody is motivated to profile them
> (with any tool), much less fix them.
well, you are assuming those latencies are visible with eyes. they might
be in extreme cases, but normally they're not (what people notices
normally are disk latencies, and few people uses an RT userspace
anyways which means they cannot claim the problem to be a lack of
cond_resched, but more likely they want shorter timeslices in the
scheduler etc..). So my point is that you need a measurement tool anyways...
next prev parent reply other threads:[~2004-10-06 4:02 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4136E7EF00073144@mail-3.tiscali.it>
2004-10-06 0:30 ` Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA) Gianluca Cecchi
2004-10-06 0:54 ` Jeff Garzik
2004-10-06 1:00 ` Preempt? (was Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA)) Roland Dreier
2004-10-06 1:11 ` Jeff Garzik
2004-10-06 1:28 ` Nick Piggin
2004-10-06 1:32 ` Nick Piggin
2004-10-06 1:40 ` Jeff Garzik
2004-10-06 1:52 ` Robert Love
2004-10-06 1:55 ` Jeff Garzik
2004-10-06 2:02 ` Nick Piggin
2004-10-06 2:07 ` Jeff Garzik
2004-10-06 2:28 ` Nick Piggin
2004-10-06 3:17 ` Andrea Arcangeli
2004-10-06 3:27 ` Jeff Garzik
2004-10-06 3:43 ` Nick Piggin
2004-10-06 3:59 ` Jeff Garzik
2004-10-06 4:05 ` Lee Revell
2004-10-06 4:22 ` Nick Piggin
2004-10-06 15:16 ` Aleksandar Milivojevic
2004-10-06 4:03 ` Andrea Arcangeli [this message]
2004-10-06 4:08 ` Jeff Garzik
2004-10-06 4:16 ` Lee Revell
2004-10-06 4:26 ` Nick Piggin
2004-10-06 4:46 ` Andrew Morton
2004-10-06 6:04 ` Jeff Garzik
2004-10-06 6:16 ` Andrew Morton
2004-10-06 13:38 ` Jeff Sipek
2004-10-06 4:12 ` Lee Revell
2004-10-06 3:34 ` Nick Piggin
2004-10-06 2:07 ` Robert Love
2004-10-06 2:30 ` Nick Piggin
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