Re: [CentOS-virt] Moving vmware guests to a CentOS KVM server

2010-02-19 Thread Kenni Lund
2010/2/18 compdoc comp...@hotrodpc.com:
 I would also just use the e1000 emulation. Theres nothing
 better about the virtio devices...

...other than lower CPU utilization and higher throughout? Since these
are CentOS/RHEL guests, I wouldn't even consider using e1000, I would
just go for virtio_net.

I don't have any links, but some time ago there were some benchmarks
(on the KVM development list?), showing the e1000 maxing out at around
300-400mbit/s while the virtio got around 900mbit/s. Even with the
much higher throughput, the virtio_net driver still had the same or
lower CPU utilization.

Do your own testing if in doubt.

Best Regards
Kenni Lund
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Re: [CentOS-virt] Moving vmware guests to a CentOS KVM server

2010-02-19 Thread S.Tindall

On Sat, 2010-02-20 at 02:41 +0100, Kenni Lund wrote:
 2010/2/18 compdoc comp...@hotrodpc.com:
  I would also just use the e1000 emulation. Theres nothing
  better about the virtio devices...
 
 ...other than lower CPU utilization and higher throughout? Since these
 are CentOS/RHEL guests, I wouldn't even consider using e1000, I would
 just go for virtio_net.
 
 I don't have any links, but some time ago there were some benchmarks
 (on the KVM development list?), showing the e1000 maxing out at around
 300-400mbit/s while the virtio got around 900mbit/s. Even with the
 much higher throughput, the virtio_net driver still had the same or
 lower CPU utilization.
 
 Do your own testing if in doubt.
 
 Best Regards
 Kenni Lund

Are you using test-signed drivers or do you have a redistributable
source for release-signed drivers (that chain to a microsoft root)?

Of course, things are much simpler if you are using 32-bit M$ guests.

Never got the chance to test relative performance of e1000 vs the netkvm
drivers on a M$ guest, but on a centos5 guest, virtio absolutely blows
the doors off e1000 performance.

Using ttcp in both directions, typical C5-host-to-C5-guests for e1000
was in the 30-60MB/s range and virtio was in the 300-400MB/s range.


Steve


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