> Datum: 30/10/07 10:38 PM > Van: "Daniel Walker" > Aan: gerritbinnenmars@xxxxxxxxxx > CC: linux-rt-users@xxxxxxxxxxxxxxx > Onderwerp : Re: CONFIG_CRITICAL_IRQSOFF_TIMING > > On Tue, 2007-10-30 at 22:26 +0100, Gerrit Binnenmars wrote: > > > Daniel, I first applied the rt patchset and then the LTTng patch > > (http://ltt.polymtl.ca/lttng/patch-2.6.22.1-rt4-lttng-0.9.10.tar.gz). > > Then LTT can be selected in the Instrumentation part of the config file. > > further ltt-control is needed (http://ltt.polymtl.ca/lttng/ltt-control-0.43-10082007.tar.gz) > > > > The viewer is only working on i386 but that is not really a problem. > > > > So, I applied the available patches without doing anything special. > > Ok . > > > Is LTT causing troubles with the preempt_max_latency options? > > I doubt it .. I haven't used the histogram options in a month or so .. > But if I remember correctly the value of preempt_max_latency is suppose > to remain at zero .. Usually preempt_max_latency is used to prune off > uninteresting latencies (ones under the max) but if you have the > histogram option turn on then all latencies points need to be recorded. > The data can be viewed in in /proc/latency_hist/ .. In 2.6.22 there is > no way to reset the histograms for preempt off, or interrupts off > timing. Daniel, Thanks for your suggestion. The latency_hist shows a max long value for the minimum latency. All other values remain 0. I think the tracer is not running at all, but I am not sure. I will remove the latency_hist option tomorrow and recheck preempt_max_latency. Gerrit > > Daniel > > - > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
