<br>On Sun, Oct 2, 2011 at 5:07 AM, Zheng Da <<a href="mailto:zhengda1936@gmail.com">zhengda1936@gmail.com</a>> wrote:<br>> Hello,<br>><br>> I start to use perf to profile my program, but I'm not quite sure if I<br>
> understand some events.<br><br>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:<br>
<br><a href="http://www.intel.com/Assets/en_US/PDF/manual/248966.pdf">http://www.intel.com/Assets/en_US/PDF/manual/248966.pdf</a><br><br>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).<br>
<br>> First, perf can profile bus cycles. Is it the bus cycles of FSB?<br>> Second, what is task clock? It seems to me that task clock is the<br>> ticks used by a process. It should include the ticks used in the<br>
> kernel mode and the user space mode, as long as it is used in the<br>> context of the process. I suppose it doesn't count the cycles used by<br>> the interrupts such as page faults and softirq, even though the irqs<br>
> are caused by the process. Is it correct?<br>><br>> Thanks,<br>> Da<br>><br>> _______________________________________________<br>> Kernelnewbies mailing list<br>> <a href="mailto:Kernelnewbies@kernelnewbies.org">Kernelnewbies@kernelnewbies.org</a><br>
> <a href="http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies">http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies</a><br>><br><br><br><br>-- <br>Regards,<br>Peter Teoh<br><br>