* Francis Giraldeau ([email protected]) wrote: > Hi, > > I'm doing some experiments with CPU statistics, and I think that those > computed by lttv are wrong. I did 3 tests, and for each command the time > utility was used to get a baseline, and the command has been run between > lttctl -C and lttctl -D to get a tight window around the test process. > > ================================================= > trace-bonnie.sh : start bonnie++ process for 10s > > time statistics: > real 0m10.715s > > user 0m0.420s > > sys 0m6.350s > > > lttv statistics: > > events count : 11088588 > > cpu time : 80.051904112
cpu time should be good. How many cores does you machine have ? 8 ? > > elapsed time : 544.593369365 Elapsed time is the total of the per-thread elapsed time I think (it's really been a while since I played with this code though). It would make sense if you have 54 threads in your system. I don't have entire confidence that the elapsed time is correct. > > cumulative cpu time : 6.747053976 cumulative cpu time is known to be wrong. Thanks, Mathieu > > ================================================= > sleep 1s : start a sleep of 1s > > time statistics: > real 0m1.002s > > user 0m0.000s > > sys 0m0.000s > > > lttv statistics: > events count : 94929 > > > cpu time : 7.841686487 > > elapsed time : 34.566952675 > > cumulative cpu time : 0.036465023 > > > ================================================= > trace-burn.sh 1s * 8 process simultanés > > time statistics: > real 0m1.031s > > user 0m7.650s > > sys 0m0.020s > > > lttv statistics: > events count : 95402 > > cpu time : 8.584145675 > > elapsed time : 33.845893813 > > cumulative cpu time : 0.037255816 > ================================================= > > I was expecting lttv enlapsed time to be close to real time, lttv > cumulative cpu time to be greater or equal to lttv cpu time, and lttc > cpu time to match user + sys time. Does it make sens, or maybe I'm > getting something wrong? > > Cheer, > > Francis > > > _______________________________________________ > ltt-dev mailing list > [email protected] > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
