On Thu, Aug 14, 2014 at 07:47:56PM +0200, Stephane Eranian wrote: > [+perf tool maintainers] > > On Thu, Aug 14, 2014 at 4:30 PM, Andi Kleen <a...@linux.intel.com> wrote: > > > > I understand all your points, but there's no alternative. > > The only other way would be to disable INST_RETIRED.ALL. > > > You cannot do that either. INST_RETIRED:ALL is important. > I assume the bug applies whether or not the event is used > with a filter.
> > I think we need to ensure that by looking at the perf.data file, > one can reconstruct the total number of inst_Retired:all > occurrences for the run. With a fixed period, one would do > num_samples * fixed_period. I know the Gooda tool does > that. It is used to estimate the number of events captured > vs. the number of events occurring. Is that really a problem? Normally periods are not that small, especially not for instruction retired. I don't think you can run such a small period on instruction retired for any significant time without throttling. With sensible periods, let's say >10k, the error from losing a few bits is very small. It would surprise me if you can actually measure it. There will be always much more jitter just from standard system noise. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
