Re: [patch 0/4] perf_counter tools: support annotation of live kernel modules

Ingo Molnar
2009-07-03T08:53:55Z

* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> On Fri, Jul 03, 2009 at 09:17:39AM +0200, Mike Galbraith wrote:
> > On Thu, 2009-07-02 at 14:10 +0200, Peter Zijlstra wrote:
> > > On Thu, 2009-07-02 at 09:17 +0200, Mike Galbraith wrote:
> > >
> > > > I've been pondering a perf archive tool
> > > > that would package everything that's needed to do analysis on a
> > > > different box. One big problem though, is that while you can easily
> > > > package vmlinux and modules, what about all the userland binaries? A
> > > > large perf.data and/or debug info binaries can easily make transport
> > > > impractical enough.
> > >
> > > I would simply extend the current file header with another section in
> > > which we do a structured storage of the data structures we currently
> > > build in perf-report. That is, the dso and symbol bits.
> > >
> > > If we then run perf-report on a file containing such a section we read
> > > that data instead of trying to locate them the regular way.
> >
> > That's a good idea.
> >
> > If uname doesn't match stored record time uname, you're not live, so
> > tools require an exportable perf.data. If you're not live and not on
> > the same host, annotate requires binaries appended via an export tool
> > with --sym-filter -k -u -% whatever capability.
> >
> > -Mike
>
>
> Also that would make easier the implementation of a perf compare
> thing. A perf compare may have several uses, including:
>
> (1) comparing different workloads with a same executable.
> (2) comparing different executable versions for a same workload
> (3) (1) + (2) ?
>
> For the (2), having self contained record files as operands would
> let comparisons based on symbols, pretty useful when you have to
> compare two different vmlinux (or whatever binary executable).

very good points.

Ingo