Re: wrong timestamps in ftrace?

[Ingo Molnar]

* Miklos Szeredi <miklos@xxxxxxxxxx> wrote:

> I've started playing with ftrace and timestamps seem to be
> misbehaving.
> 
> # echo 0 > /sys/kernel/debug/tracing/tracing_enabled
> # echo nop > /sys/kernel/debug/tracing/current_tracer
> # echo 131072 > /sys/kernel/debug/tracing/buffer_size_kb
> # echo sched_switch > /sys/kernel/debug/tracing/current_tracer
> # echo 1 > /sys/kernel/debug/tracing/tracing_enabled
> # sleep 10
> # echo 0 > /sys/kernel/debug/tracing/tracing_enabled
> # cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt
> # ls -lh /tmp/trace.txt
> -rw-r--r-- 1 root root 96K Mar 17 16:11 /tmp/trace.txt
> # head -5 /tmp/trace.txt | tail -1
>             bash-4908  [001]   212.139730:   4908:120:S   + [001]  4845:120:S
> # tail -1 /tmp/trace.txt
>      kondemand/1-1020  [001]   212.261054:   1020:115:S ==> [001]     0:140:R
> 
> So according to the timestamps the time difference between the first
> and last event was just 0.12s, which is rubbish.
> 
> This is latest git on a CoreDuo T60 notebook.  Attaching .config and
> dmesg.

There's been changes to timestamping in the tracing tree. Could you 
check whether latest -tip:

   http://people.redhat.com/mingo/tip.git/README

works better for you?

	Ingo
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