On Mon, Oct 29, 2012 at 12:01 PM, Dhaval Giani <dhaval.gi...@gmail.com> wrote: > Hi, > > As part of a class assignment I have to collect some performance > statistics. In order to do so I run > > perf record -g <the program I have to profile> > > And in another window, I start 200 threads of the load generator > (which is not recorded by perf) > > This generates me statistics that I expect to see, and I am happy. As > this is academia and a class assignment, I need to collect information > and analyze it across different setups. Which of course meant I script > this whole thing, which basically is > > for i in all possibilities > do > perf record -g <the program I have to profile> & > WAITPID=$! > for j in NR_THREADS > do > <start load generator> & > KILLPID=$! > done > wait $PID > kill $KILLPID > mv perf.data results/perf.data.$i > done > > (This is basic pseudo script of what I am doing), which results me > having my profile being topped by _vscanf() and the function which I > was seeing dominating in the older report dropping down to something > like 5% (as opposed to 16-17%) > > Have I misunderstood how perf works? Something deeper? I am currently > on 3.6.3. I can update to the latest upstream and report back. Any > debug code is very welcome. I can also make my toy program and the > scripts available for you to try out.
I just updated to 6b0cb4eef7bdaa27b8021ea81813fba330a2d94d and I still see this happen. Thanks! Dhaval -- 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/
