On Fri, Nov 08, 2013 at 03:23:07PM -0500, Vince Weaver wrote: > On Fri, 8 Nov 2013, Frederic Weisbecker wrote: > > > > There seem to be a loop that takes too long in intel_pmu_handle_irq(). Your > > two > > previous reports seemed to suggest that lbr is involved, but not this one. > > I may be wrong but I think everything between <NMI> and <EOE> is just > noise from the NMI perf-event watchdog timer kicking in.
Ah good point. So the pattern seem to be that irq work/perf_event_wakeup is involved, may be interrupting a tracepoint event or so. It would be nice if you enable CONFIG_FRAME_POINTER in your future reports so that we get more precise traces. Or may be you actually enabled it and it doesn't work? > Why that code would be reading the LBR registers I don't know. Yeah that's just an inconditional call to check if there is lbr branch to record. > Vince > > -- 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/
