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From: "Lee Revell" <rlrevell@joe-job.com>
To: "Hans-Peter Jansen" <hpj@urpla.net>
Cc: linux-kernel@vger.kernel.org,
	"Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>,
	"Soeren Sonnenburg" <kernel@nn7.de>
Subject: Re: prioritize PCI traffic ?
Date: Fri, 26 Jan 2007 19:32:40 -0500	[thread overview]
Message-ID: <75b66ecd0701261632q1a93b487u81539d850df10db0@mail.gmail.com> (raw)
In-Reply-To: <200701172122.27407.hpj@urpla.net>

On 1/17/07, Hans-Peter Jansen <hpj@urpla.net> wrote:
> Am Montag, 15. Januar 2007 15:53 schrieb Vaidyanathan Srinivasan:
> >
> > 33Mhz 32-bit PCI bus on typical PC can do around 100MB/sec...
>
> Substract roughly n * 5MB for VIA chipsets, where n is the age (1 <= n <=
> 4), and even more for SIS, ATI..

While developing the latency tracer in the -rt kernel, Ingo and others
discovered that some SATA controllers can produce very bad DMA
starvation at higher speeds.  A latency trace of such an event looks
like the entire system is going in slow motion.  Presumably, vendors
do this to improve benchmark scores.

Try forcing your drives to a lower speed.

Lee

  reply	other threads:[~2007-01-27  0:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-15 11:07 Soeren Sonnenburg
2007-01-15 12:01 ` Andreas Mohr
2007-01-15 12:07   ` Soeren Sonnenburg
2007-01-15 13:53 ` Vaidyanathan Srinivasan
2007-01-15 14:00   ` Soeren Sonnenburg
2007-01-15 14:53     ` Vaidyanathan Srinivasan
2007-01-17 20:22       ` Hans-Peter Jansen
2007-01-27  0:32         ` Lee Revell [this message]
     [not found] <fa.IZ3qyPHQu5qQWnA4jBWoHC54zJE@ifi.uio.no>
2007-01-15 14:24 ` Robert Hancock

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