Re: [PATCH v5 06/20] perf: Add AUX record

[Alexander Shishkin]

Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:

> On Mon, Oct 13, 2014 at 04:45:34PM +0300, Alexander Shishkin wrote:
>> +	/*
>> +	 * Records that new data landed in the AUX buffer part.
>> +	 *
>> +	 * struct {
>> +	 * 	struct perf_event_header	header;
>> +	 *
>> +	 * 	u64				aux_offset;
>> +	 * 	u64				aux_size;
>> +	 *	u64				flags;
>> +	 * 	struct sample_id		sample_id;
>> +	 * };
>> +	 */
>> +	PERF_RECORD_AUX				= 11,
>
> Given the discussion with the ARM people the last time, do we want to
> add the possibility of a variable data field in this event? Its easy to
> add now, harder to do later (although not impossible).

Iirc, what they want is to save a once-per-session chunk of data, which
would be better synthesized by perf record than sent from a pmu driver?

We do something like that with PT right now, perf record looks at pmu's
sysfs attributes and stores them in some synthesized record.

> Also added Mathieu Poirier on CC, he asked to be included in your next
> postings.

Indeed, my apologies.

Regards,
--
Alex
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