Messages in this thread | | | Subject | Re: [PATCH 2/4] tracing: add event trace infrastructure | From | Pekka Enberg <> | Date | Wed, 25 Feb 2009 11:33:07 +0200 |
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Hi Andrew,
On Wed, 2009-02-25 at 01:22 -0800, Andrew Morton wrote: > irqsoff latency trace v1.1.5 on 2.6.26-rc8 > -------------------------------------------------------------------- > latency: 97 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) > ----------------- > | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) > ----------------- > => started at: apic_timer_interrupt > => ended at: do_softirq
<the header seems broken here, should have # at the beginning of the line>
> > # _------=> CPU# > # / _-----=> irqs-off > # | / _----=> need-resched > # || / _---=> hardirq/softirq > # ||| / _--=> preempt-depth > # |||| / > # ||||| delay > # cmd pid ||||| time | caller > # \ / ||||| \ | / > <idle>-0 0d..1 0us+: trace_hardirqs_off_thunk (apic_timer_interrupt) > <idle>-0 0d.s. 97us : __do_softirq (do_softirq) > <idle>-0 0d.s1 98us : trace_hardirqs_on (do_softirq) > > your time starts now.
Well, what do you want to know? The first thing to do here is to:
$ grep -v "#" trace <idle>-0 0d..1 0us+: trace_hardirqs_off_thunk (apic_timer_interrupt) <idle>-0 0d.s. 97us : __do_softirq (do_softirq) <idle>-0 0d.s1 98us : trace_hardirqs_on (do_softirq)
after which you have access to the raw data. This particular trace seems to be somewhat hard to parse (because not all fields are whitespace delimited) but I can assure you that any format I rely on is not.
So if you're arguing against specific ftrace plugins, go ahead (you probably have a fair point there). But please don't dismiss the while _concept_ of ftrace because of them.
Pekka
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