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From: Marinos Yannikos <mjy@geizhals.at>
To: linux-kernel@vger.kernel.org
Subject: gdth / SCSI read performance issues (2.2.19 and 2.4.10)
Date: Wed, 24 Oct 2001 14:22:16 +0200	[thread overview]
Message-ID: <3BD6B278.3070300@geizhals.at> (raw)

Hi,

our brand-new ICP GDT8523RZ controller with 6 disks peaks out at
45MB/s under 2.4.10, while with 2.2.19 it reaches 85MB/s (seq.
read performance). It should realistically be able to reach
at least 150-200MB/s in this configuration (RAID-5, 6 disks,
it's a 64-bit 66MHz PCI card). It's in a dual P3-1GHz box with
Tyan 2510NG board. Sequential write performance is OK with both
kernels, it's higher than the read performance on 2.4.10 (60MB/s).

Under 2.4.10, when I test the performance with a simple program
that just read()'s 16MB blocks from /dev/sda, both CPUs report
40-50% System time usage. 2.2.19 reports ~20% for one CPU (and
better performance).

Is there anything that can be done about this? It seems like a
serious performance problem either with the gdth driver or the
kernel and it renders this neat controller rather ineffective.

Regards,
-mjy
[please CC: answers]


             reply	other threads:[~2001-10-24 12:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-24 12:22 Marinos Yannikos [this message]
2001-10-24 16:31 ` Andrew Morton
2001-10-24 20:51   ` Marinos J. Yannikos
2001-10-24 21:28     ` Andrew Morton
2001-10-24 22:55       ` Marinos J. Yannikos

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