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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: Adrian 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2019-04-12 14:38:29 +03:00 committed by Arnaldo Carvalho de Melo
parent 3cd3216dbb
commit c7b4f15ff7
1 changed files with 39 additions and 1 deletions
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40
tools/perf/util/intel-pt.c
View File

@ -1914,6 +1914,44 @@ static int intel_pt_process_switch(struct intel_pt *pt,
return machine__set_current_tid(pt->machine, cpu, -1, tid); 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, static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event,
struct perf_sample *sample) 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 (pt->have_sched_switch == 3) {
if (!out) if (!out)
return 0; return intel_pt_context_switch_in(pt, sample);
if (event->header.type != PERF_RECORD_SWITCH_CPU_WIDE) { if (event->header.type != PERF_RECORD_SWITCH_CPU_WIDE) {
pr_err("Expecting CPU-wide context switch event\n"); pr_err("Expecting CPU-wide context switch event\n");
return -EINVAL; return -EINVAL;