On Wed, 22 Jul 2015, Peter Zijlstra wrote: > On Tue, Jul 21, 2015 at 04:08:28PM -0400, Vince Weaver wrote: > > On Tue, 21 Jul 2015, Peter Zijlstra wrote: > > > > > On Tue, Jul 21, 2015 at 02:14:54PM -0400, Vince Weaver wrote: > > > > Hello > > > > > > > > I have a new AMD A8 system and perf multiplexing support is acting > > > > weird. > > > > > > > > If I run the perf_event_tests check_multiplexing test it fails like > > > > this: > > > > > > > > Event TotalCount RawCount Scale > > > > ScaledCount Error > > > > 0 500282143 150403975 -2.00 (c8050b5 > > > > fffffffff9c224ef) -300807950 160.13% > > > > > > > > So the problem is that the TOTAL_TIME_RUNNING value is negative, which > > > > as > > > > far as I know shouldn't be possible. > > > > > > Correct, that should not happen. I don't have a Fam16 machine, but I can > > > try and stare at the code a wee bit. Although there's another few perf > > > issues I am still looking into as well :/ > > > > well I've traced it back to see that in > > update_event_times() > > run_end is less than event->tstamp_running, which is why the result > > is negative. > > > > [ 1279.857205] VMW: 1 run_end=1279846999345 tstamp_running=1279929016607 > > [ 1279.857222] VMW: 0 run_end=1279855184453 tstamp_running=1279931111760 > > > > It seems to happen both in the PERF_EVENT_STATE_INACTIVE and > > !PERF_EVENT_STATE_INACTIVE cases. > > > > tracking back why those values are wrong is proving to be a bit trickier. > > Can you run with something like the below?
OK, so I have to admit I'm a bit weak on ftrace. What type of command line are you interested in seeing? The ones I've tried with trace-cmd have activated your trace_printks but there's 500MB of other data mixed in so maybe I am doing something wrong. Vince -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
