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 > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
