Re: [PATCH v9 06/14] perf: Add AUX record

[Adrian Hunter]

On 24/03/15 13:07, Jiri Olsa wrote:
> On Wed, Jan 14, 2015 at 02:18:15PM +0200, Alexander Shishkin wrote:
>> When there's new data in the AUX space, output a record indicating its
>> offset and size and a set of flags, such as PERF_AUX_FLAG_TRUNCATED, to
>> mean the described data was truncated to fit in the ring buffer.
>>
>> Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx>
>> ---
>>  include/uapi/linux/perf_event.h | 19 +++++++++++++++++++
>>  kernel/events/core.c            | 34 ++++++++++++++++++++++++++++++++++
>>  kernel/events/internal.h        |  3 +++
>>  3 files changed, 56 insertions(+)
>>
>> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
>> index b7ccdf5e93..2d40e2aa07 100644
>> --- a/include/uapi/linux/perf_event.h
>> +++ b/include/uapi/linux/perf_event.h
>> @@ -746,6 +746,20 @@ enum perf_event_type {
>>  	 */
>>  	PERF_RECORD_MMAP2			= 10,
>>  
>> +	/*
>> +	 * 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;
> 
> hum, I dont see sample_id below in implementation

Alex is away, so I will take the liberty of answering.

perf_event_aux_event() calls perf_event__output_id_sample()
That's it isn't it?

> 
> jirka
> 
>> +	 * };
>> +	 */
>> +	PERF_RECORD_AUX				= 11,
>> +
>>  	PERF_RECORD_MAX,			/* non-ABI */
>>  };
>>  
>> @@ -763,6 +777,11 @@ enum perf_callchain_context {
>>  	PERF_CONTEXT_MAX		= (__u64)-4095,
>>  };
>>  
>> +/**
>> + * PERF_RECORD_AUX::flags bits
>> + */
>> +#define PERF_AUX_FLAG_TRUNCATED		0x01	/* record was truncated to fit */
>> +
>>  #define PERF_FLAG_FD_NO_GROUP		(1UL << 0)
>>  #define PERF_FLAG_FD_OUTPUT		(1UL << 1)
>>  #define PERF_FLAG_PID_CGROUP		(1UL << 2) /* pid=cgroup id, per-cpu mode only */
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index a6a145ad0b..4e17393264 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -5648,6 +5648,40 @@ void perf_event_mmap(struct vm_area_struct *vma)
>>  	perf_event_mmap_event(&mmap_event);
>>  }
>>  
>> +void perf_event_aux_event(struct perf_event *event, unsigned long head,
>> +			  unsigned long size, u64 flags)
>> +{
>> +	struct perf_output_handle handle;
>> +	struct perf_sample_data sample;
>> +	struct perf_aux_event {
>> +		struct perf_event_header	header;
>> +		u64				offset;
>> +		u64				size;
>> +		u64				flags;
>> +	} rec = {
>> +		.header = {
>> +			.type = PERF_RECORD_AUX,
>> +			.misc = 0,
>> +			.size = sizeof(rec),
>> +		},
>> +		.offset		= head,
>> +		.size		= size,
>> +		.flags		= flags,
>> +	};
>> +	int ret;
>> +
>> +	perf_event_header__init_id(&rec.header, &sample, event);
>> +	ret = perf_output_begin(&handle, event, rec.header.size);
>> +
>> +	if (ret)
>> +		return;
>> +
>> +	perf_output_put(&handle, rec);
>> +	perf_event__output_id_sample(event, &handle, &sample);
>> +
>> +	perf_output_end(&handle);
>> +}
>> +
>>  /*
>>   * IRQ throttle logging
>>   */
>> diff --git a/kernel/events/internal.h b/kernel/events/internal.h
>> index 0f6d080159..4d117a9814 100644
>> --- a/kernel/events/internal.h
>> +++ b/kernel/events/internal.h
>> @@ -62,6 +62,9 @@ static inline bool rb_has_aux(struct ring_buffer *rb)
>>  	return !!rb->aux_nr_pages;
>>  }
>>  
>> +void perf_event_aux_event(struct perf_event *event, unsigned long head,
>> +			  unsigned long size, u64 flags);
>> +
>>  extern void
>>  perf_event_header__init_id(struct perf_event_header *header,
>>  			   struct perf_sample_data *data,
>> -- 
>> 2.1.4
>>
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> 
> 

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