Commit c7b4f15f authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
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perf intel-pt: Improve sync_switch by processing PERF_RECORD_SWITCH* in events 



sync_switch is a facility to synchronize decoding more closely with the
point in the kernel when the context actually switched.

Improve it by processing "context switch in" events.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190412113830.4126-8-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3cd3216d

tools/perf/util/intel-pt.c

+39 −1
Original line number Diff line number Diff line
@@ -1914,6 +1914,44 @@ static int intel_pt_process_switch(struct intel_pt *pt, 
	return machine__set_current_tid(pt->machine, cpu, -1, tid);

}



static int intel_pt_context_switch_in(struct intel_pt *pt,

				      struct perf_sample *sample)

{

	pid_t pid = sample->pid;

	pid_t tid = sample->tid;

	int cpu = sample->cpu;



	if (pt->sync_switch) {

		struct intel_pt_queue *ptq;



		ptq = intel_pt_cpu_to_ptq(pt, cpu);

		if (ptq && ptq->sync_switch) {

			ptq->next_tid = -1;

			switch (ptq->switch_state) {

			case INTEL_PT_SS_NOT_TRACING:

			case INTEL_PT_SS_UNKNOWN:

			case INTEL_PT_SS_TRACING:

				break;

			case INTEL_PT_SS_EXPECTING_SWITCH_EVENT:

			case INTEL_PT_SS_EXPECTING_SWITCH_IP:

				ptq->switch_state = INTEL_PT_SS_TRACING;

				break;

			default:

				break;

			}

		}

	}



	/*

	 * If the current tid has not been updated yet, ensure it is now that

	 * a "switch in" event has occurred.

	 */

	if (machine__get_current_tid(pt->machine, cpu) == tid)

		return 0;



	return machine__set_current_tid(pt->machine, cpu, pid, tid);

}



static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event,

				   struct perf_sample *sample)

{
@@ -1925,7 +1963,7 @@ static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event, 


	if (pt->have_sched_switch == 3) {

		if (!out)

			return 0;

			return intel_pt_context_switch_in(pt, sample);

		if (event->header.type != PERF_RECORD_SWITCH_CPU_WIDE) {

			pr_err("Expecting CPU-wide context switch event\n");

			return -EINVAL;