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[Xen-users] Poor hard disk performance on xen-3/dom0

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] Poor hard disk performance on xen-3/dom0
From: Woon Wai Keen <list+xen@xxxxxxxxxxxxxx>
Date: Tue, 27 Dec 2005 01:39:50 +0800
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On a vanilla 2.6.12 kernel, I get:

  60MB/s for hdparm -t /dev/sd[a|b] (on an Intel ICH7 SATA controller).
  30MB/s for hdparm -t /dev/hda (Intel ICH7)

While on the xen dom0 kernel, I get 20MB/s for all three devices. I confirm that DMA is enabled for the PATA hard disk. I don't know how to check that for the SATA hard disks, but I assume that they're on DMA mode too.

Xen is compiled with the following:

xen_changeset          : Fri Dec  9 11:05:06 2005 +0000 8311:53cff3f88e45
cc_compiler            : gcc version 3.3.5 (Debian 1:3.3.5-13)

The dom0 kernel is compiled with almost the same options as the vanilla kernel, barring the xen-exclusive and nonxen-exclusive options.

Does anyone else face similar problems?

wK (www.doubleukay.com)

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