* Martin.Wirth@xxxxxx | 2016-02-19 17:02:20 [+0000]: >Hi, Hi, >I today switched from 4.1.15-rt17 to 4.4.1-rt6. >Now I'm seeing large latencies of more than 1 ms. >They occur sporadic ( every few minutes) and show up for example running > >cyclictest -l10000000 -m -Sp99 -i200 > >I tried to catch a trace and got the following: > > > <...>-3709 2d...2.. 2us : set_next_entity <-pick_next_task_fair > <...>-3709 2d...2.. 2us : update_stats_wait_end <-set_next_entity > firefox-3736 2d...2.. 3us : finish_task_switch <-__schedule > firefox-3736 2d...2.. 3us#: _raw_spin_unlock_irq <-finish_task_switch > firefox-3736 2d...... 1091us : smp_apic_timer_interrupt <-apic_timer_interrupt > firefox-3736 2d...... 1092us : irq_enter <-smp_apic_timer_interrupt >Does the above trace ring a bell or is it useless? This does not ring a bell. According to the trace your CPU took a break after the unlock until the next interrupt. If this a fucntion trace I would expect some functions after that. You could try the v4.4 line as of: v4.4-rt2 v4.4-rt3 v4.4.1-rt5 to see if I introduced this somewhere by accident. However I haven't seen this on any of my boxes. >Thanks, > >Martin Sebastian -- 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
