* David Ahern <[email protected]> wrote:
> > Well, we could exclude the profiling task itself from profiling
> > events (just like ftrace and core bits of perf does it out of
> > necessity), but I intentionally wanted to avoid that, to make sure
> > we are honest and to make sure people don't tolerate profiling
> > overhead that disturbs other workloads.
>
> Samples generated by perf itself need to be observable -- e.g.
> process scheduling I want to see the time consumed by the data
> collector itself and there are times when 'perf trace -- perf ...'
> is useful.
Absolutely agreed - a measurement instrument affects the measurement,
and we must not try to hide that.
Still we can try to make the disturbance smaller and more managable.
For example if I have enough RAM it should be possible to run perf
record with a 1 GB ring-buffer, and in that case as long as the
perf.data is smaller than 1 GB there should be no writeout or any
other IO activity until the measurement ends.
Thanks,
Ingo
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