The link below gives a very good user guide of perf. http://code.google.com/p/kernel/wiki/PerfUserGuide#Sampling_with_perf_record Da On Sun, Oct 9, 2011 at 10:11 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: > This is from LinuxKongress 2010: > > The New Linux 'perf' Tools - Vger > > http://vger.kernel.org/~acme/perf/lk2010-perf-paper.pdf > > http://www.linux-kongress.org/2010/slides/lk2010-perf-acme.pdf > > Enjoy.... > > On Sun, Oct 9, 2011 at 2:42 AM, Zheng Da <zhengda1936@xxxxxxxxx> wrote: >> Hey Peter, >> >> If you are talking about the documentation of performance counters, we >> can find very complete reference >> http://software.intel.com/sites/products/documentation/hpc/amplifierxe/en-us/lin/ug_docs/reference/index.htm >> >> Thanks, >> Da >> >> On Sat, Oct 8, 2011 at 11:18 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: >>> >>> >>> On Thu, Oct 6, 2011 at 10:39 PM, Zheng Da <zhengda1936@xxxxxxxxx> wrote: >>>> >>>> Thank you, Peter. I didn't realize Intel has explained all performance >>>> counters in its manual, and I was desperately looking for more >>>> detailed explanation on the Internet. >>>> >>>> On Mon, Oct 3, 2011 at 11:19 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> >>>> wrote: >>>> > >>>> > >>>> > On Tue, Oct 4, 2011 at 9:53 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> >>>> > wrote: >>>> >> >>>> >> On Sun, Oct 2, 2011 at 5:07 AM, Zheng Da <zhengda1936@xxxxxxxxx> wrote: >>>> >> > Hello, >>>> >> > >>>> >> > I start to use perf to profile my program, but I'm not quite sure if >>>> >> > I >>>> >> > understand some events. >>>> >> >>>> >> Firstly perf is using hardware to read these performance information. >>>> >> So >>>> >> for intel CPU, depending on the different model, u can find the >>>> >> relevant >>>> >> information in the reference manual from Intel here: >>>> >> >>>> >> http://www.intel.com/Assets/en_US/PDF/manual/248966.pdf >>>> >> >>>> >> In particular, the various model of Intel CPU is listed in page xvii, >>>> >> and >>>> >> along with it are the various performance information u can extract out >>>> >> - >>>> >> the last item is the BUS information (B.6.10). >>>> >> >>>> >> > First, perf can profile bus cycles. Is it the bus cycles of FSB? >>>> >> > Second, what is task clock? It seems to me that task clock is the >>>> > >>>> > task clock, from reading the implementation in kernel/events/core.c, i >>>> > suspect is a software event, not hardware. Ie, it counts upon each >>>> > task >>>> > switch. To quote from core.c: >>>> > /* >>>> > * Software event: task time clock >>>> > */ >>>> > static void task_clock_event_update(struct perf_event *event, u64 now) >>>> > { >>>> > >>>> > More details here: >>>> > http://lwn.net/Articles/312720/ >>>> > >>>> >> >>>> >> > ticks used by a process. It should include the ticks used in the >>>> >> > kernel mode and the user space mode, as long as it is used in the >>>> >> > context of the process. I suppose it doesn't count the cycles used by >>>> >> > the interrupts such as page faults and softirq, even though the irqs >>>> >> > are caused by the process. Is it correct? >>>> > >>>> > on the contrary, i think it should include, as to exclude these cycles >>>> > does >>>> > entail stopping the hrtimer.....read into core.c further. >>>> I'm disappointed that the information isn't documented somewhere. The >>>> developers shouldn't expect users to read the code to understand how >>>> to use the tool :( >>>> >>> >>> i suspect it is documented in many places, at here is one good one: >>> http://developer.apple.com/library/IOS/#documentation/DeveloperTools/Conceptual/SharkUserGuide/MiscellaneousTopics/MiscellaneousTopics.html#//apple_ref/doc/uid/TP40005233-CH14-SW3 >>> and from the side, looking at Appendix A, u can see a table of all the >>> PerfCounters for ARM11, and then another section will list out for Intel, >>> and then PPC etc..... >>> >>>> >>>> BTW, is there any wiki where people can share what they found in the >>>> kernel? >>>> >>>> Thanks, >>>> Da >>> >>> >>> >>> -- >>> Regards, >>> Peter Teoh >>> >> > > > > -- > Regards, > Peter Teoh > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
