From: William Lee Irwin III <wli@holomorphy.com>
To: Per Andreas Buer <perbu@linpro.no>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.4: mylex and > 2GB RAM
Date: Mon, 8 Dec 2003 12:22:29 -0800 [thread overview]
Message-ID: <20031208202229.GO8039@holomorphy.com> (raw)
In-Reply-To: <PERBUMSGID-ul6d6azt6b0.fsf@nfsd.linpro.no>
William Lee Irwin III <wli@holomorphy.com> writes:
>> If your memory ended at 2GB and the driver had 31-bit DMA, it may have
>> decided to use unconstrained allocations. Then, when you added more RAM,
>> it was forced to ask for <= 896MB, which made it copy to buffers that are
>> actually below 896MB most of the time.
On Mon, Dec 08, 2003 at 09:15:15PM +0100, Per Andreas Buer wrote:
> But this would reduce the throuput only a few percent, right? My system
> slows down from writing ~ 100MB/s to maybe 50KB/s.
It could potentially slow it down a lot more than a few percent.
The main effect you would see is heavy low memory consumption (LowFree:
going down to almost nothing) and very heavy cpu consumption.
-- wli
next prev parent reply other threads:[~2003-12-08 20:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-08 15:24 2.4: mylex and > 2GB RAM Per Buer
2003-12-08 15:36 ` William Lee Irwin III
2003-12-08 15:54 ` Per Buer
2003-12-08 16:22 ` William Lee Irwin III
2003-12-08 20:15 ` Per Andreas Buer
2003-12-08 20:22 ` William Lee Irwin III [this message]
2003-12-08 21:01 ` Per Andreas Buer
2003-12-08 21:02 ` William Lee Irwin III
2003-12-08 21:25 ` Per Andreas Buer
2003-12-08 21:36 ` William Lee Irwin III
2003-12-09 10:31 ` Marcelo Tosatti
2003-12-10 13:21 ` Per Buer
2003-12-08 20:40 ` Zwane Mwaikambo
2003-12-08 15:58 Hank Leininger
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