Re: [PATCH 2/4] tracing: add event trace infrastructure

From: Ingo Molnar
Date: Wed Feb 25 2009 - 05:35:30 EST



* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, 2009-02-25 at 01:22 -0800, Andrew Morton wrote:
>
> > Parse this:
> >
> > 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
> >
> > # _------=> 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.
>
> awk '/^#/ { start=1; next } { if (!start) next; .... }'

yeah.

For /debug/tracing/trace the convention is that a simple:

grep -v '^#'

pattern will filter out the header as "comments".

Ingo
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