[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-users] Release 0.9.10 of GPL PV Drivers for Windows
> for 0.9.10: > For a tcp test, 'iperf-1.7.0 -c dom0-name -t 60 -r': > > domu->dom0: 37.5 Mb/s (better) > dom0->domu: 101 Mb/s (wow!) > > While I would love it if the two directions were more equal, it's > definitely > better for the download speeds to be better than the upload if I can only > pick one ;-) > > (Playing with all combinations of csum and lso off and on resulted in > minor differences.) Off the top of my head, here are a list of reasons why performance might not be all that it could be: 1. Linux supports Large Send and Large Receive (for when a Large Send packet doesn't get routed out of physical hardware). Windows can do Large Send but cannot handle Large Receive, so I have to fake it by splitting up the large packet into smaller ones and re-calculating checksums. 2. Windows seems to only ever give me one packet in its 'SendPackets' routine, which will obviously result in higher per-packet overheads than if it could batch them (eg we potentially have to 'notify' dom0 of a new packet each time instead of having to batch them). Large Send may lessen that problem a bit though. 3. We don't try and do any interrupt moderation or anything. 4. We try and be a bit conservative with resources (eg packet buffers etc). So there is a chance of getting a bit more performance out of it yet... James _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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