Re: [PATCH 00/14] [GIT PULL][v2.6.39] tracing/filter: More robust filtering

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Em Wed, Feb 16, 2011 at 10:34:07PM +0900, Masami Hiramatsu escreveu:
> (2011/02/16 3:35), Arnaldo Carvalho de Melo wrote:

> > Yeah, usability of the --filter parameter in perf is a bit
> > (understatement) lacking, one has to look at the /format thing in
> > /sys/kernel/debug/tracing... and not commit any mistake, else a generic
> > invalid 22 message is spit out.

> And also, there seems very less comment in perf-record.txt.

> --filter=<filter>::
>         Event filter.

> Hmm, I think, at least, there should be a comment where user should
> refer to and if possible, how he can use it...

> > I tried it and after some back and forth changing hats and scratching my
> > head while doing so, it got to work.

> > I talked with Steven and the same operation using trace-cmd would
> > produce a better error report, stating that the field used in the filter
> > expression was not valid.

> If possible, please show us what parameters we can use on that event too.
> perf list gives us a list of events, but not show us what parameters
> we can use on those events. I think we can update perf list for that
> purpose.

> e.g.)
> perf list --field kvm:kvm_entry
>  unsigned short common_type;
>  unsigned char common_flags;
>  unsigned char common_preempt_count;
>  int common_pid;
>  int common_lock_depth;
>  unsigned int vcpu_id;

That is a cool idea, I would accept a patch implementing this :-)

- Arnaldo