Messages in this thread | | | Date | Fri, 4 Jan 2013 12:57:14 +0100 | Subject | Re: [PATCH net-next] softirq: reduce latencies | From | Sedat Dilek <> |
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On Fri, Jan 4, 2013 at 5:41 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > 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 >
I also wanted to give some numbers. But with localhost as default (no netserver running on a remote-host) I am not sure if these numbers give any helpful feedback. ( I have not tested yet w/o your patch. )
- Sedat - # netperf -H localhost -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 localhost (127.0.0.1) port 0 AF_INET : demo : first burst 0 : cpu bind RT_LATENCY=11.407 MIN_LATENCY=10 MAX_LATENCY=152 P50_LATENCY=11 P90_LATENCY=12 P99_LATENCY=13 MEAN_LATENCY=11.31 STDDEV_LATENCY=0.95
# netperf -H localhost -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 localhost (127.0.0.1) port 0 AF_INET : demo : first burst 0 : cpu bind RT_LATENCY=11.364 MIN_LATENCY=10 MAX_LATENCY=156 P50_LATENCY=11 P90_LATENCY=12 P99_LATENCY=13 MEAN_LATENCY=11.27 STDDEV_LATENCY=1.06
# netperf -H localhost -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 localhost (127.0.0.1) port 0 AF_INET : demo : first burst 0 : cpu bind RT_LATENCY=11.408 MIN_LATENCY=10 MAX_LATENCY=156 P50_LATENCY=11 P90_LATENCY=12 P99_LATENCY=13 MEAN_LATENCY=11.31 STDDEV_LATENCY=1.07
# netperf -H localhost -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 localhost (127.0.0.1) port 0 AF_INET : demo : first burst 0 : cpu bind RT_LATENCY=11.312 MIN_LATENCY=10 MAX_LATENCY=151 P50_LATENCY=11 P90_LATENCY=12 P99_LATENCY=13 MEAN_LATENCY=11.22 STDDEV_LATENCY=0.94
# netperf -H localhost -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 localhost (127.0.0.1) port 0 AF_INET : demo : first burst 0 : cpu bind RT_LATENCY=11.345 MIN_LATENCY=10 MAX_LATENCY=159 P50_LATENCY=11 P90_LATENCY=12 P99_LATENCY=13 MEAN_LATENCY=11.25 STDDEV_LATENCY=1.03
-dileks // 04-Jan-2013
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