perf cs-etm: Introduce the concept of trace ID queues

In an ideal world there is one CPU per cs_etm_queue and as such, one
trace ID per cs_etm_queue.  In the real world CoreSight topologies allow
multiple CPUs to use the same sink, which translates to multiple trace
IDs per cs_etm_queue.

To deal with this a new cs_etm_traceid_queue structure is introduced to
enclose all the information related to a single trace ID, allowing a
cs_etm_queue to handle traces generated by any number of CPUs.
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/20190524173508.29044-10-mathieu.poirier@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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

@@ -413,8 +413,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
 	struct cs_etm_queue *etmq = decoder->data;
 	struct cs_etm_packet_queue *packet_queue;
 
-	/* First get the packet queue */
-	packet_queue = cs_etm__etmq_get_packet_queue(etmq);
+	/* 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;
 

tools/perf/util/cs-etm.h

@@ -136,6 +136,16 @@ struct cs_etm_packet {
 
 #define CS_ETM_PACKET_MAX_BUFFER 1024
 
+/*
+ * When working with per-thread scenarios the process under trace can
+ * be scheduled on any CPU and as such, more than one traceID may be
+ * associated with the same process.  Since a traceID of '0' is illegal
+ * as per the CoreSight architecture, use that specific value to
+ * identify the queue where all packets (with any traceID) are
+ * aggregated.
+ */
+#define CS_ETM_PER_THREAD_TRACEID 0
+
 struct cs_etm_packet_queue {
 	u32 packet_count;
 	u32 head;
@@ -172,7 +182,7 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
 				  struct perf_session *session);
 int cs_etm__get_cpu(u8 trace_chan_id, int *cpu);
 struct cs_etm_packet_queue
-*cs_etm__etmq_get_packet_queue(struct cs_etm_queue *etmq);
+*cs_etm__etmq_get_packet_queue(struct cs_etm_queue *etmq, u8 trace_chan_id);
 #else
 static inline int
 cs_etm__process_auxtrace_info(union perf_event *event __maybe_unused,
@@ -188,7 +198,8 @@ static inline int cs_etm__get_cpu(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)
+				struct cs_etm_queue *etmq __maybe_unused,
+				u8 trace_chan_id __maybe_unused)
 {
 	return NULL;
 }