On Thu, 2013-01-03 at 11:41 -0800, Rick Jones wrote: > In terms of netperf overhead, once you specify P99_LATENCY, you are > already in for the pound of cost but only getting the penny of output > (so to speak). While it would clutter the output, one could go ahead > and ask for the other latency stats and it won't "cost" anything more: > > ... -- -k > RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY > > Additional information about how the omni output selectors work can be > found at > http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#Omni-Output-Selection > > happy benchmarking, > > rick jones > > BTW - you will likely see some differences between RT_LATENCY, which is > calculated from the average transactions per second, and MEAN_LATENCY, > which is calculated from the histogram of individual latencies > maintained when any of the _LATENCY outputs other than RT_LATENCY is > requested. Kudos to the folks at Google who did the extensions to the > then-existing histogram code to enable it to be used for more reasonably > accurate statistics. >
Yeah ;) Here are the before/after_patch results, cpu 2 handling the NIC irqs : Before patch : # netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind RT_LATENCY=550110.424 MIN_LATENCY=146858 MAX_LATENCY=997109 P50_LATENCY=305000 P90_LATENCY=550000 P99_LATENCY=710000 MEAN_LATENCY=376989.12 STDDEV_LATENCY=184046.92 After patch : # netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind RT_LATENCY=40545.492 MIN_LATENCY=9834 MAX_LATENCY=78366 P50_LATENCY=33583 P90_LATENCY=59000 P99_LATENCY=69000 MEAN_LATENCY=38364.67 STDDEV_LATENCY=12865.26 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
