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
