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RE: [Xen-users] Another GPLPV pre-release 0.9.11-pre20

"James Harper" <james.harper@xxxxxxxxxxxxxxxx> wrote on 05.11.2008 11:49:18:

> Based on that, I'll get you to try some tcpdumps with offload enabled.
> If you want to do them straight away, we are looking for:
> Dom0<->WinDomU - incorrect checksums
> Bacula<->WinDomU - outgoing packets from each machine have bad checksum,
> incoming packets have good checksum
> In Dom0 I really need to see tcpdump's of the vif interface, the bridge
> interface, and the peth0.13 interface.

I tcpdumped my remote desktop connection (checksum offload enabled, large send offload enabled):
Showed incorrect cksums on vif65.0 and br13 interfaces, but no incorrect cksums on peth0.13 i quess you are right, Linux does calculate correct tcp chsums when it send them off to the wire...?

Also when i did iperf between dom0 <-> winDomU with large send offload enabled and checksum offload enabled i get this:
C:\TEMP>iperf -s -w1M
Server listening on TCP port 5001
TCP window size: 1.00 MByte
[1872] local 213.250.XX.XX port 5001 connected with 213.250.DOM.0 port 43323
[ ID] Interval       Transfer     Bandwidth
[1872]  0.0-10.0 sec  1.06 GBytes   912 Mbits/sec

I retested that couple times and allways about 910-920 Mbit/sec, so when i enable checksum offload it goes from 1.59 Gbits/sec -> 912Mbit.

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