Re: [RFC PATCH 0/7] perf: 'live mode'

From: Ingo Molnar
Date: Thu Mar 04 2010 - 12:15:50 EST

* Tom Zanussi <tzanussi@xxxxxxxxx> wrote:

> Currently, a perf session entails two steps: first 'perf record' or 'perf
> trace record' records the perf data to disk, then 'perf report' or 'perf
> trace report' reads the saved data from disk and reports the results.
> This experimental patchset makes some changes to perf that instead allow the
> perf data to be piped directly from the record step to the report step,
> without ever touching the disk.

Very nice!

> Obviously, it would be better to have a real top-like display for these
> rather than a continuously scrolling mode like this, and of course it will
> be much more useful once we get the syscall name injection events going (the
> column on the left shows syscall numbers only).

It's still useful for ad-hoc tracing!

Side-note, it might make sense to expose the 'clear' escape sequence somehow
in an easy fashion:

to make it non-scrolling ;-) via a pre-provided method.

> There are some rough edges and inefficiencies, and I guess 'event injection'
> may be a better way to do this in the end, but it seems to work pretty well
> already, and I think it shows how useful such a capability can be.

I'm all for it. Frederic, Steve, what do you think?

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