From: Eric Mudama <edmudama@gmail.com>
To: Brad Campbell <brad@wasp.net.au>
Cc: linux-ide@vger.kernel.org
Subject: Re: sata_promise performance observations
Date: Mon, 25 Oct 2004 11:55:28 -0600 [thread overview]
Message-ID: <311601c904102510555d7c0810@mail.gmail.com> (raw)
In-Reply-To: <417A1826.5010502@wasp.net.au>
arbitration between the multiple PCI cards? A single card that
doesn't have to compete for PCI resources would, in theory, be
faster...
(Don't know much about this chunk of hardware, 'tis only a guess)
On Sat, 23 Oct 2004 12:36:54 +0400, Brad Campbell <brad@wasp.net.au> wrote:
> G'day all,
>
> Interesting observation with 3 SATA150TX4 cards and 10 Maxtor Maxline-II 250GB SATA drives.
>
> If I run a concurrent dd if=/dev/sda > /dev/null and dd if=/dev/sdb > /dev/null I get the expected
> 115MB/s transfer rates in vmstat.
>
> If I do a dd if=/dev/sda > /dev/null and dd if=/dev/sde > /dev/null I get about 80MB/s
>
> sda, sde & sdi I get
> procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
>
> 3 0 22540 2560 463908 5320 0 0 85294 16 1102 761 11 88 0 1
> 3 1 22540 1480 464852 5320 0 0 86493 25 987 512 13 86 0 0
> 2 2 22540 2176 464304 5268 0 0 86774 18 1091 721 12 87 0 1
> 2 2 22540 1488 464860 5368 0 0 85562 18 921 416 13 87 0 0
>
> When streaming from drives not on the same controller, I lose about 30mb/s transfer rate. In fact,
> it seems to max out at about 86MB/s no matter what combination of drives I use if I stream from more
> than one controller.
>
> However, if I use sda, sbb & sdc I get
>
> procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
>
> 0 3 22512 1768 464448 5304 0 0 121661 18 1257 566 9 59 0 32
> 0 3 22512 1536 464696 5316 0 0 122903 14 1262 578 10 59 0 31
> 0 3 22512 2112 464228 5268 0 0 121655 14 1255 578 9 60 0 32
>
> How bizzare. I have latency set to 32 on all controllers, but I have tried as low as 8 and as high
> as 128 to no avail.
>
> I have readahead set to 4096 on all devices.
>
> Anyone have any ideas?
>
> Not that this is an issue for me (I'm only using it as a fileserver over GB eth so its not like
> 100MB/s is actually required, just an interesting observation)
>
> Regards,
> Brad
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prev parent reply other threads:[~2004-10-25 17:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-23 8:36 sata_promise performance observations Brad Campbell
2004-10-25 17:55 ` Eric Mudama [this message]
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