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Commit 675f302f authored by Mathieu Poirier's avatar Mathieu Poirier Committed by Arnaldo Carvalho de Melo
Browse files

perf cs-etm: Add notion of time to decoding code 



This patch deals with timestamp packets received from the decoding
library in order to give the front end packet processing loop a handle
on the time instruction conveyed by range packets have been executed at.

Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: default avatarLeo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190524173508.29044-17-mathieu.poirier@linaro.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0a6be300

tools/perf/util/cs-etm-decoder/cs-etm-decoder.c

+107 −4
Original line number Diff line number Diff line
@@ -269,6 +269,75 @@ cs_etm_decoder__create_etm_packet_printer(struct cs_etm_trace_params *t_params, 
						     trace_config);

}



static ocsd_datapath_resp_t

cs_etm_decoder__do_soft_timestamp(struct cs_etm_queue *etmq,

				  struct cs_etm_packet_queue *packet_queue,

				  const uint8_t trace_chan_id)

{

	/* No timestamp packet has been received, nothing to do */

	if (!packet_queue->timestamp)

		return OCSD_RESP_CONT;



	packet_queue->timestamp = packet_queue->next_timestamp;



	/* Estimate the timestamp for the next range packet */

	packet_queue->next_timestamp += packet_queue->instr_count;

	packet_queue->instr_count = 0;



	/* Tell the front end which traceid_queue needs attention */

	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);



	return OCSD_RESP_WAIT;

}



static ocsd_datapath_resp_t

cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq,

				  const ocsd_generic_trace_elem *elem,

				  const uint8_t trace_chan_id)

{

	struct cs_etm_packet_queue *packet_queue;



	/* First get the packet queue for this traceID */

	packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id);

	if (!packet_queue)

		return OCSD_RESP_FATAL_SYS_ERR;



	/*

	 * We've seen a timestamp packet before - simply record the new value.

	 * Function do_soft_timestamp() will report the value to the front end,

	 * hence asking the decoder to keep decoding rather than stopping.

	 */

	if (packet_queue->timestamp) {

		packet_queue->next_timestamp = elem->timestamp;

		return OCSD_RESP_CONT;

	}



	/*

	 * This is the first timestamp we've seen since the beginning of traces

	 * or a discontinuity.  Since timestamps packets are generated *after*

	 * range packets have been generated, we need to estimate the time at

	 * which instructions started by substracting the number of instructions

	 * executed to the timestamp.

	 */

	packet_queue->timestamp = elem->timestamp - packet_queue->instr_count;

	packet_queue->next_timestamp = elem->timestamp;

	packet_queue->instr_count = 0;



	/* Tell the front end which traceid_queue needs attention */

	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);



	/* Halt processing until we are being told to proceed */

	return OCSD_RESP_WAIT;

}



static void

cs_etm_decoder__reset_timestamp(struct cs_etm_packet_queue *packet_queue)

{

	packet_queue->timestamp = 0;

	packet_queue->next_timestamp = 0;

	packet_queue->instr_count = 0;

}



static ocsd_datapath_resp_t

cs_etm_decoder__buffer_packet(struct cs_etm_packet_queue *packet_queue,

			      const u8 trace_chan_id,
@@ -310,7 +379,8 @@ cs_etm_decoder__buffer_packet(struct cs_etm_packet_queue *packet_queue, 
}



static ocsd_datapath_resp_t

cs_etm_decoder__buffer_range(struct cs_etm_packet_queue *packet_queue,

cs_etm_decoder__buffer_range(struct cs_etm_queue *etmq,

			     struct cs_etm_packet_queue *packet_queue,

			     const ocsd_generic_trace_elem *elem,

			     const uint8_t trace_chan_id)

{
@@ -365,6 +435,23 @@ cs_etm_decoder__buffer_range(struct cs_etm_packet_queue *packet_queue, 


	packet->last_instr_size = elem->last_instr_sz;



	/* per-thread scenario, no need to generate a timestamp */

	if (cs_etm__etmq_is_timeless(etmq))

		goto out;



	/*

	 * The packet queue is full and we haven't seen a timestamp (had we

	 * seen one the packet queue wouldn't be full).  Let the front end

	 * deal with it.

	 */

	if (ret == OCSD_RESP_WAIT)

		goto out;



	packet_queue->instr_count += elem->num_instr_range;

	/* Tell the front end we have a new timestamp to process */

	ret = cs_etm_decoder__do_soft_timestamp(etmq, packet_queue,

						trace_chan_id);

out:

	return ret;

}
@@ -372,6 +459,11 @@ static ocsd_datapath_resp_t 
cs_etm_decoder__buffer_discontinuity(struct cs_etm_packet_queue *queue,

				     const uint8_t trace_chan_id)

{

	/*

	 * Something happened and who knows when we'll get new traces so

	 * reset time statistics.

	 */

	cs_etm_decoder__reset_timestamp(queue);

	return cs_etm_decoder__buffer_packet(queue, trace_chan_id,

					     CS_ETM_DISCONTINUITY);

}
@@ -404,6 +496,7 @@ cs_etm_decoder__buffer_exception_ret(struct cs_etm_packet_queue *queue, 


static ocsd_datapath_resp_t

cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,

			struct cs_etm_packet_queue *packet_queue,

			const ocsd_generic_trace_elem *elem,

			const uint8_t trace_chan_id)

{
@@ -417,6 +510,12 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq, 
	if (cs_etm__etmq_set_tid(etmq, tid, trace_chan_id))

		return OCSD_RESP_FATAL_SYS_ERR;



	/*

	 * A timestamp is generated after a PE_CONTEXT element so make sure

	 * to rely on that coming one.

	 */

	cs_etm_decoder__reset_timestamp(packet_queue);



	return OCSD_RESP_CONT;

}
@@ -446,7 +545,7 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( 
							    trace_chan_id);

		break;

	case OCSD_GEN_TRC_ELEM_INSTR_RANGE:

		resp = cs_etm_decoder__buffer_range(packet_queue, elem,

		resp = cs_etm_decoder__buffer_range(etmq, packet_queue, elem,

						    trace_chan_id);

		break;

	case OCSD_GEN_TRC_ELEM_EXCEPTION:
@@ -457,11 +556,15 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( 
		resp = cs_etm_decoder__buffer_exception_ret(packet_queue,

							    trace_chan_id);

		break;

	case OCSD_GEN_TRC_ELEM_TIMESTAMP:

		resp = cs_etm_decoder__do_hard_timestamp(etmq, elem,

							 trace_chan_id);

		break;

	case OCSD_GEN_TRC_ELEM_PE_CONTEXT:

		resp = cs_etm_decoder__set_tid(etmq, elem, trace_chan_id);

		resp = cs_etm_decoder__set_tid(etmq, packet_queue,

					       elem, trace_chan_id);

		break;

	case OCSD_GEN_TRC_ELEM_ADDR_NACC:

	case OCSD_GEN_TRC_ELEM_TIMESTAMP:

	case OCSD_GEN_TRC_ELEM_CYCLE_COUNT:

	case OCSD_GEN_TRC_ELEM_ADDR_UNKNOWN:

	case OCSD_GEN_TRC_ELEM_EVENT:

tools/perf/util/cs-etm.c

+19 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ struct cs_etm_queue { 
	struct cs_etm_decoder *decoder;

	struct auxtrace_buffer *buffer;

	unsigned int queue_nr;

	u8 pending_timestamp;

	u64 offset;

	const unsigned char *buf;

	size_t buf_len, buf_used;
@@ -133,6 +134,19 @@ int cs_etm__get_cpu(u8 trace_chan_id, int *cpu) 
	return 0;

}



void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,

					      u8 trace_chan_id)

{

	/*

	 * Wnen a timestamp packet is encountered the backend code

	 * is stopped so that the front end has time to process packets

	 * that were accumulated in the traceID queue.  Since there can

	 * be more than one channel per cs_etm_queue, we need to specify

	 * what traceID queue needs servicing.

	 */

	etmq->pending_timestamp = trace_chan_id;

}



static void cs_etm__clear_packet_queue(struct cs_etm_packet_queue *queue)

{

	int i;
@@ -942,6 +956,11 @@ int cs_etm__etmq_set_tid(struct cs_etm_queue *etmq, 
	return 0;

}



bool cs_etm__etmq_is_timeless(struct cs_etm_queue *etmq)

{

	return !!etmq->etm->timeless_decoding;

}



static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,

					    struct cs_etm_traceid_queue *tidq,

					    u64 addr, u64 period)

tools/perf/util/cs-etm.h

+17 −0
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ struct cs_etm_packet_queue { 
	u32 packet_count;

	u32 head;

	u32 tail;

	u32 instr_count;

	u64 timestamp;

	u64 next_timestamp;

	struct cs_etm_packet packet_buffer[CS_ETM_PACKET_MAX_BUFFER];

};
@@ -183,6 +186,9 @@ int cs_etm__process_auxtrace_info(union perf_event *event, 
int cs_etm__get_cpu(u8 trace_chan_id, int *cpu);

int cs_etm__etmq_set_tid(struct cs_etm_queue *etmq,

			 pid_t tid, u8 trace_chan_id);

bool cs_etm__etmq_is_timeless(struct cs_etm_queue *etmq);

void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,

					      u8 trace_chan_id);

struct cs_etm_packet_queue

*cs_etm__etmq_get_packet_queue(struct cs_etm_queue *etmq, u8 trace_chan_id);

#else
@@ -207,6 +213,17 @@ static inline int cs_etm__etmq_set_tid( 
	return -1;

}



static inline bool cs_etm__etmq_is_timeless(

				struct cs_etm_queue *etmq __maybe_unused)

{

	/* What else to return? */

	return true;

}



static inline void cs_etm__etmq_set_traceid_queue_timestamp(

				struct cs_etm_queue *etmq __maybe_unused,

				u8 trace_chan_id __maybe_unused) {}



static inline struct cs_etm_packet_queue *cs_etm__etmq_get_packet_queue(

				struct cs_etm_queue *etmq __maybe_unused,

				u8 trace_chan_id __maybe_unused)