Hi, I get the same thing with my own little multithreaded benchmark.
I think it has to do with what happens in per-thread/per-cpu mode with inheritance. I think each events of the child threads are propagated to each parent. I get 12x the amount on my 12 CPUs workstation. If you drop -i in task_cpu, then you only capture one thread's execution across all the CPUs. In per-thread mode + inehritance + cpu, it seems the kernel aggregates per PID and not per TID. Not sure this was intended. I think for what you are after, you need to get system-wide with per CPU breakdown: $ perf stat -a -A -e instructions ./binary Then the counts will add up. On Mon, Sep 9, 2013 at 6:44 PM, Bhavishya Goel <bhavishya.g...@gmail.com> wrote: > Yes, that's what I am doing. Below is an example of the counts I get from > task vs task_cpu from a 4-threaded binary: > > $> task -i -e INSTRUCTIONS_RETIRED ./binary > > 27 708 362 452 INSTRUCTIONS_RETIRED > > $> task_cpu -i -e INSTRUCTIONS_RETIRED ./binary > CPU0 29 529 250 689 INSTRUCTIONS_RETIRED > > CPU1 26 991 683 307 INSTRUCTIONS_RETIRED > > CPU2 24 404 405 488 INSTRUCTIONS_RETIRED > > CPU3 30 442 586 081 INSTRUCTIONS_RETIRED > > Adding up the task_cpu counts from all 4 CPUs will give me instructions > retired count which is almost four times of what I get from task. And I know > the count from task is correct because this is very close to what I get from > Intel PCM-TSX tool. Can you tell me what am I doing wrong? > > > > On Mon, Sep 9, 2013 at 4:46 PM, Stephane Eranian <eran...@googlemail.com> > wrote: >> >> On Mon, Sep 9, 2013 at 4:35 PM, Bhavishya Goel <bhavishya.g...@gmail.com> >> wrote: >> > It is multi-threaded. >> > >> > >> Then you need to add up all the counts from all the CPUs. >> >> > On Mon, Sep 9, 2013 at 4:26 PM, Stephane Eranian >> > <eran...@googlemail.com> >> > wrote: >> >> >> >> On Tue, Sep 3, 2013 at 8:51 AM, Bhavishya Goel >> >> <bhavishya.g...@gmail.com> >> >> wrote: >> >> > Hi, >> >> > >> >> > I am using "task_cpu" example in perf_examples folder of libpfm4.4 >> >> > (linux >> >> > kernel 3.11-rc7, micrarchitecture: haswell). The counter numbers that >> >> > I >> >> > get >> >> > from task_cpu seem to be wrong as they are vastly different than what >> >> > I >> >> > get >> >> > from "task" example and Intel's PCM-TSX tool. This is an example of >> >> > command >> >> > line I use: >> >> > >> >> > task_cpu -i -e INSTRUCTIONS_RETIRED ./binary >> >> > >> >> > task -i -e INSTRUCTIONS_RETIRED ./binary >> >> > >> >> > The counter numbers from task_cpu are almost double of numbers from >> >> > task. >> >> > While, the numbers from PCM-TSX match the numbers from task. Is it a >> >> > bug >> >> > of >> >> > am I doing something wrong? >> >> > >> >> Sorry for late reply. >> >> Is your binary multi-process or multi-thread? >> >> >> >> > -- >> >> > ಠ_ಠ >> >> > >> >> > >> >> > >> >> > ------------------------------------------------------------------------------ >> >> > Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, >> >> > more! >> >> > Discover the easy way to master current and previous Microsoft >> >> > technologies >> >> > and advance your career. Get an incredible 1,500+ hours of >> >> > step-by-step >> >> > tutorial videos with LearnDevNow. Subscribe today and save! >> >> > >> >> > >> >> > http://pubads.g.doubleclick.net/gampad/clk?id=58040911&iu=/4140/ostg.clktrk >> >> > _______________________________________________ >> >> > perfmon2-devel mailing list >> >> > perfmon2-devel@lists.sourceforge.net >> >> > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel >> >> > >> > >> > >> > >> > >> > -- >> > ಠ_ಠ > > > > > -- > ಠ_ಠ ------------------------------------------------------------------------------ Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! Discover the easy way to master current and previous Microsoft technologies and advance your career. Get an incredible 1,500+ hours of step-by-step tutorial videos with LearnDevNow. Subscribe today and save! http://pubads.g.doubleclick.net/gampad/clk?id=58041391&iu=/4140/ostg.clktrk _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
