Yes, but the values displayed (column 6) are obviously not the time in ns since epoch. They seem to be nano-seconds passed since processor reset. I just need to understand how this field is computed from sched_clock().
thanks, - nagy stephane eranian wrote: > On Thu, Jan 22, 2009 at 4:46 PM, Nagy Mostafa <nagy.most...@gmail.com> wrote: > >> Hi Stephane, >> >> I am a little confused now. I thought perfmon uses TSC to timestamp samples. >> For example, the pfmon command: >> >> $ pfmon --smpl-module=compact --with-header >> -emy_event,unhalted_reference_cycles --long-smpl-periods=140000 >> my_program >> >> gives: >> >> >> # description of columns: >> # column 1: entry number >> # column 2: process id >> # column 3: thread id >> # column 4: cpu number >> # column 5: instruction pointer >> # column 6: unique timestamp >> # column 7: overflowed PMD index >> # column 8: event set >> # column 9: initial value of overflowed PMD (sampling period) >> # followed by optional sampled PMD values in command line order >> # >> # >> 0 5854 5854 3 0x400621 0x0000002aaadf4476 17 0 >> -140000 0x3363c >> 1 5854 5854 3 0x400621 0x0000002aaae0b512 17 0 >> -140000 0x66c78 >> 2 5854 5854 3 0x400621 0x0000002aaae21813 17 0 >> -140000 0x9a2bd >> 3 5854 5854 3 0x400621 0x0000002aaae37a5c 17 0 >> -140000 0xcd8f9 >> 4 5854 5854 3 0x400621 0x0000002aaae4dc69 17 0 >> -140000 0x100f3e >> 5 5854 5854 3 0x400621 0x0000002aaae63e67 17 0 >> -140000 0x134583 >> >> So, column #6 is the TSC value divided by the CPU freq (i.e. time from reset >> in ns). >> You mentioned a tstamp field in the sample that relies on sched_clock(). Is >> that another timestamp field ? If yes, how can I display it using pfmon ? >> >> > We are talking about the same field: tstamp = sched_clock(). > This is the only field. If you try to divide by CPU freq then you will likely > be > affected by scaling. You can lock your CPU at a fixed frequency via /sys. > I think there exists a command to get/set frequency. > > ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
