Re: [PATCH 1/2] Does raw_field_ptr() supports __data_loc?

From: Steven Rostedt
Date: Mon Dec 07 2009 - 11:09:42 EST


On Mon, 2009-12-07 at 12:34 +0900, Hitoshi Mitake wrote:
> VERY very sorry for my long silence...
>
> Please don't commit this patch, Ingo.
> This patch is required to test the next patch for perf lock.
>
> I have a question for Steven Rostedt and Tom Zanussi.
> Does current raw_field_ptr() support __data_loc?
>
> At 064739bc4b3d7f424b2f25547e6611bcf0132415 ,
> support for the modifier "__data_loc" of format is added.
>
> But, when I wanted to parse format of lock_acquired (or some event else),
> raw_field_ptr() did not returned correct pointer.
>
> So I modified raw_field_ptr() like this patch. Then raw_field_ptr() works well.
> Parser was large so I'd like to ask you about this.
>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
> Cc: Steven Rostedt <srostedt@xxxxxxxxxx>
>
> I have a question
> ---
> tools/perf/util/trace-event-parse.c | 7 +++++++
> 1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> index 0302405..494a470 100644
> --- a/tools/perf/util/trace-event-parse.c
> +++ b/tools/perf/util/trace-event-parse.c
> @@ -1925,6 +1925,13 @@ void *raw_field_ptr(struct event *event, const char *name, void *data)
> if (!field)
> return NULL;
>
> + if (field->flags & FIELD_IS_STRING) {
> + int offset;
> + offset = *(int *)(data + field->offset);
> + offset &= 0xffff;
> + return data + offset;
> + }
> +

Hmm, I guess I need to update the code in perf again. The way I did this
was to have FIELD_IS_STRING evaluated in the eval_num_arg.


-- Steve

> return data + field->offset;
> }
>

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