From: James Andrewartha <jamesa@daa.com.au>
To: linux-ide@vger.kernel.org
Subject: High iowait and poor performance - ata_piix
Date: Mon, 15 Aug 2005 17:34:25 +0800 [thread overview]
Message-ID: <430061A1.2040806@daa.com.au> (raw)
Hi,
I've got a Proliant DL360 G4 (dual 3.4GHz Xeon, 1GB ram), which has the
Intel E7520 chipset and uses ata_piix. I'm getting some very high iowait -
6-10% while idle, and 40-70% while processing mail (which is
postfix+dpsam/postgresql). I've tried the ubuntu packages for 2.6.{10,11,12}
with no change.
I also noticed some odd results with bonnie++ - it's slower writing per
block than per character (although block writing uses a lot less cpu):
2.6.11 on a Seagate ST3160827AS (160GB 7200.7):
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
quoll 4G 22016 42 20982 7 15462 3 32869 56 39013 4 155.9 0
2.6.12 on a Maxtor 6Y080M0 (80GB DiamondPlus 9):
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
quoll-maxtor 4G 30381 53 28041 5 16912 3 35664 61 57015 7 108.3 0
The Seagate results were done on a lvm on raid 1, while the Maxtor was just
on an lvm, and neither disk was under any significant load while testing
(mail was turned off). For reference, a 200GB Seagate 7200.7 on a dual
opteron 242 with 2GB ram and the promise SX8 controller (using the driver
from the promise website):
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
martello-seagate 4G 40457 96 58846 28 18211 6 29935 64 62569 8 199.3 0
Unfortunately there's no option in the BIOS to use AHCI mode (if it's even
possible on this chipset), and it's 1RU system so I can't use another
controller. Any suggestions on working out what's wrong?
--
James Andrewartha
Systems Administrator
Data Analysis Australia Pty Ltd
reply other threads:[~2005-08-15 9:34 UTC|newest]
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