On Fri, 2006-03-03 at 18:32 +0100, Guennadi Liakhovetski wrote: > On Thu, 2 Mar 2006, Lee Revell wrote: > > > On Fri, 2006-03-03 at 00:13 +0100, Guennadi Liakhovetski wrote: > > > On Thu, 2 Mar 2006, Lee Revell wrote: > > > > > > > Try enabling latency tracing in the kernel config and see what you get > > > > in /proc/latency_trace. > > > > That's for user triggered latency tracing, you want the standard kernel > > latency tracer: > > > > echo 1 > /proc/sys/kernel/trace_enabled > > echo 0 > /proc/sys/kernel/preempt_max_latency > > Aha, that was the key:-) > > > Then try nice -n -20 arecord ..., once you get some underruns: > > > > cat /proc/latency_trace > > Ok, there's "nothing" there - nothing near the xrun value I've just got: > > overrun!!! (at least 35.525 ms long) > > and in /proc/latency_trace > > preemption latency trace v1.1.5 on 2.6.15.4-rt16 > -------------------------------------------------------------------- > latency: 64 us, #36/36, CPU#0 | (M:rt VP:0, KP:0, SP:1 HP:1) > ----------------- > | task: softirq-timer/0-3 (uid:0 nice:0 policy:1 rt_prio:1) > ----------------- > > _------=> CPU# > / _-----=> irqs-off > | / _----=> need-resched > || / _---=> hardirq/softirq > ||| / _--=> preempt-depth > |||| / > ||||| delay > cmd pid ||||| time | caller > \ / ||||| \ | / > pdflush-104 0D.h3 0us : __trace_start_sched_wakeup (try_to_wake_up) > pdflush-104 0D.h3 1us : __trace_start_sched_wakeup <<...>-3> (62 0) > pdflush-104 0Dnh2 1us : try_to_wake_up <<...>-3> (62 74) > pdflush-104 0Dnh2 1us : check_raw_flags (try_to_wake_up) > pdflush-104 0Dnh1 2us : preempt_schedule (try_to_wake_up) > pdflush-104 0Dnh1 2us : wake_up_process (wakeup_softirqd) > pdflush-104 0Dnh1 3us : check_raw_flags (raise_softirq) > pdflush-104 0Dnh1 3us : rcu_pending (update_process_times) > pdflush-104 0Dnh1 3us : scheduler_tick (update_process_times) > pdflush-104 0Dnh1 3us : sched_clock (scheduler_tick) > pdflush-104 0Dnh2 4us : task_timeslice (scheduler_tick) > pdflush-104 0Dnh1 5us : preempt_schedule (scheduler_tick) > pdflush-104 0Dnh1 5us : softlockup_tick (update_process_times) > pdflush-104 0Dnh2 6us : note_interrupt (__do_IRQ) > pdflush-104 0Dnh2 6us : enable_8259A_irq (__do_IRQ) > pdflush-104 0Dnh3 8us : check_raw_flags (enable_8259A_irq) > pdflush-104 0Dnh2 8us : preempt_schedule (enable_8259A_irq) > pdflush-104 0Dnh1 8us : preempt_schedule (__do_IRQ) > pdflush-104 0Dnh1 9us : irq_exit (do_IRQ) > pdflush-104 0Dn.1 9us+< (608) > pdflush-104 0.n.. 41us : preempt_schedule (_mmx_memcpy) > pdflush-104 0Dn.. 41us : __schedule (preempt_schedule) > pdflush-104 0Dn.. 41us : profile_hit (__schedule) > pdflush-104 0Dn.1 42us : sched_clock (__schedule) > pdflush-104 0D..2 42us+: trace_array (__schedule) > pdflush-104 0D..2 47us : trace_array <<...>-3> (62 62) > pdflush-104 0D..2 48us : trace_array <pdflush-104> (74 78) > pdflush-104 0D..2 49us : trace_array <<...>-2984> (76 78) > pdflush-104 0D..2 50us+: trace_array (__schedule) > <...>-3 0D..2 59us : __switch_to (__schedule) > <...>-3 0D..2 60us : __schedule <pdflush-104> (74 62) > <...>-3 0...1 61us : trace_stop_sched_switched (__schedule) > <...>-3 0D..2 62us : trace_stop_sched_switched <<...>-3> (62 0) > <...>-3 0D..2 63us : trace_stop_sched_switched (__schedule) > > > vim:ft=help > > Then I tried switching lapic again on, then removing "nmi_watchdog=2", and > even "acpi=off" - nothing helps. No more ideas... What now? Can we do some > smart arecord profiling?...
So the scheduler is OK. Try it with the standard kernel. You may need to go back through previous kernel version to identify exactly when it broke. Lee ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
