Re: [Xen-users] Re: Performance Issues: I/O Wait

["Nick Couchman" <Nick.Couchman@xxxxxxxxx>]

Stephan,
Thanks for the tips - I'll give them a try.  One clarification - for
disabling transmission checksums, is that inside the domU or inside
dom0?

Some of the tests was using NFS, but lately I've been testing with iSCSI
and even local block devices and it seems to happen on those, too,
though not to the same degree.

Thanks,

Nick Couchman
SEAKR Engineering, Inc.
6221 South Racine Circle
Centennial, CO 80111
Main: (303) 790-8499
Fax: (303) 790-8720
Web: http://www.seakr.com
>>> Stephan Seitz <s.seitz@xxxxxxxxxxxx> 10/23/07 8:03 PM >>>
Nick Couchman schrieb:
> Hi, again...haven't had any responses to this, yet.
> 
> Thanks,
> Nick

Hi,

have you tried to pin your vCPU's to dedicated Cores?
It might be suboptimal if a domU uses.. say core 0 of
cpu 0 and core 0 of cpu 1 ... or anything not on the
same cpu.
config:
e.g. use the second cpu on a 2x dualcore system
count starts at 0.
cpus = [ 2,3 ]


If your domU is bridged, you might try to disable
transmission checksums on the NIC's.
ethtool -K [nicname] tx off

Anyway, you mentioned high I/O latency due to network
issues. Is your domU using some kind of NFS or something?
Btw. I might missed this part, but are you using PV or
HVM guests?

Greetings


-- 
Stephan Seitz
Senior System Administrator

*netz-haut* e.K.
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97074 wÃrzburg

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