> So it won't be all that simple to implement well, and before we try, > I'd like to know whether there are applications that are helped > by it. For example, we could try to measure latency at various > pps and see whether the backpressure helps. netperf has -b, -w > flags which might help these measurements. Those options are enabled when one adds --enable-burst to the pre-compilation ./configure of netperf (one doesn't have to recompile netserver). However, if one is also looking at latency statistics via the -j option in the top-of-trunk, or simply at the histogram with --enable-histogram on the ./configure and a verbosity level of 2 (global -v 2) then one wants the very top of trunk netperf from: http://www.netperf.org/svn/netperf2/trunk to get the recently added support for accurate (netperf level) RTT measuremnts on burst-mode request/response tests. happy benchmarking, rick jones PS - the enhanced latency statistics from -j are only available in the "omni" version of the TCP_RR test. To get that add a --enable-omni to the ./configure - and in this case both netperf and netserver have to be recompiled. For very basic output one can peruse the output of: src/netperf -t omni -- -O /? and then pick those outputs of interest and put them into an output selection file which one then passes to either (test-specific) -o, -O or -k to get CVS, "Human" or keyval output respectively. E.G. raj@tardy:~/netperf2_trunk$ cat foo THROUGHPUT,THROUGHPUT_UNITS RT_LATENCY,MIN_LATENCY,MEAN_LATENCY,MAX_LATENCY P50_LATENCY,P90_LATENCY,P99_LATENCY,STDDEV_LATENCY when foo is passed to -o one will get those all on one line of CSV. To -O one gets three lines of more netperf-classic-like "human" readable output, and when one passes that to -k one gets a string of keyval output a la: raj@tardy:~/netperf2_trunk$ src/netperf -t omni -j -v 2 -- -r 1 -d rr -k foo OMNI TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET : histogram THROUGHPUT=29454.12 THROUGHPUT_UNITS=Trans/s RT_LATENCY=33.951 MIN_LATENCY=19 MEAN_LATENCY=32.00 MAX_LATENCY=126 P50_LATENCY=32 P90_LATENCY=38 P99_LATENCY=41 STDDEV_LATENCY=5.46 Histogram of request/response times UNIT_USEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 TEN_USEC : 0: 3553: 45244: 237790: 7859: 86: 10: 3: 0: 0 HUNDRED_USEC : 0: 2: 0: 0: 0: 0: 0: 0: 0: 0 UNIT_MSEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 TEN_MSEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 HUNDRED_MSEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 UNIT_SEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 TEN_SEC : 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 >100_SECS: 0 HIST_TOTAL: 294547 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
