On Wed, 2009-10-07 at 19:10 +0200, Frans Pop wrote: > On Tuesday 06 October 2009, Frans Pop wrote: > > I've checked for 2.6.31.1 now and iwlagn is listed high there too when > > the system is idle, but with normal values of 60-100 ms. And phy0 has > > normal values of below 10 ms. > > I've now rebooted with today's mainline git; phy0 now frequently shows > > with values of around 100 ms too (i.e. higher than last time). > > > > Both still go way down as soon as the system is given work to do. > > > > With a 5 second sleep I was unable to get any significant latencies (I > > started perf on a latencytop refresh and did a manual refresh as it > > finished to see what happened during the perf run). The perf run does > > seem to affect the latencies. > > I've uploaded a chart for a 10s sleep during which I got latencies of > > 101ms for iwlagn and 77ms for phy0: > > http://people.debian.org/~fjp/tmp/kernel/. > > Mike privately sent me a script to try to capture the latencies with perf, > but the perf output does not show any high latencies at all. It looks as if > we may have found a bug in latencytop here instead. Maybe. I have a little perturbation measurement proggy which I just fired up to verify both perf and latencytop's numbers here. It's a dirt simply cycle counter tool, which calibrates itself, sums perturbations over a period of time and emit stats. Here, all three are in violent agreement wrt how long "pert" is waiting for cpu. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
