On 6/29/11 1:42 AM, "Michael S. Tsirkin" <[email protected]> wrote: > >> >roprabhu, Tom, >> > >> >Thanks very much for the testing. So on the first glance >> >one seems to see a significant performance gain in V0 here, >> >and a slightly less significant in V2, with V1 >> >being worse than base. But I'm afraid that's not the >> >whole story, and we'll need to work some more to >> >know what really goes on, please see below. >> > >> > >> >Some comments on the results: I found out that V0 because of mistake >> >on my part was actually almost identical to base. >> >I pushed out virtio-net-limit-xmit-polling/v1a instead that >> >actually does what I intended to check. However, >> >the fact we get such a huge distribution in the results by Tom >> >most likely means that the noise factor is very large. >> > >> > >> >From my experience one way to get stable results is to >> >divide the throughput by the host CPU utilization >> >(measured by something like mpstat). >> >Sometimes throughput doesn't increase (e.g. guest-host) >> >by CPU utilization does decrease. So it's interesting. >> > >> > >> >Another issue is that we are trying to improve the latency >> >of a busy queue here. However STREAM/MAERTS tests ignore the latency >> >(more or less) while TCP_RR by default runs a single packet per queue. >> >Without arguing about whether these are practically interesting >> >workloads, these results are thus unlikely to be significantly affected >> >by the optimization in question. >> > >> >What we are interested in, thus, is either TCP_RR with a -b flag >> >(configure with --enable-burst) or multiple concurrent >> >TCP_RRs. > > ok sounds good. I am testing your v1a patch. Will try to get some results out > end of this week. Thanks. >
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