From: Mathieu Poirier mathieu.poirier@linaro.org

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: Mathieu Poirier mathieu.poirier@linaro.org Tested-by: Leo 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: Arnaldo Carvalho de Melo acme@redhat.com --- .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 111 +++++++++++++++++- tools/perf/util/cs-etm.c | 19 +++ tools/perf/util/cs-etm.h | 17 +++ 3 files changed, 143 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c index ce85e52f989c..bb45e23018ee 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -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: diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 17adf554b679..91496a3a2209 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -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) diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h index b2a7628620bf..33b57e748c3d 100644 --- a/tools/perf/util/cs-etm.h +++ b/tools/perf/util/cs-etm.h @@ -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)