From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: sata_promise performance observations Date: Sat, 23 Oct 2004 12:36:54 +0400 Sender: linux-ide-owner@vger.kernel.org Message-ID: <417A1826.5010502@wasp.net.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wasp.net.au ([203.190.192.17]:23494 "EHLO wasp.net.au") by vger.kernel.org with ESMTP id S267170AbUJWIgd (ORCPT ); Sat, 23 Oct 2004 04:36:33 -0400 List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org 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