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perf thread-stack: Fix thread stack processing for the idle task

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perf creates a single 'struct thread' to represent the idle task. That
is because threads are identified by PID and TID, and the idle task
always has PID == TID == 0.

However, there are actually separate idle tasks for each CPU. That
creates a problem for thread stack processing which assumes that each
thread has a single stack, not one stack per CPU.

Fix that by passing through the CPU number, and in the case of the idle
"thread", pick the thread stack from an array based on the CPU number.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20181221120620.9659-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter
2018-12-21 14:06:19 +02:00
committed by Arnaldo Carvalho de Melo
parent 139f42f3b3
commit 256d92bc93
5 changed files with 69 additions and 25 deletions
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6
tools/perf/util/intel-pt.c
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@@ -1174,7 +1174,7 @@ static void intel_pt_prep_sample(struct intel_pt *pt,
intel_pt_prep_b_sample(pt, ptq, event, sample);
if (pt->synth_opts.callchain) {
thread_stack__sample(ptq->thread, ptq->chain,
thread_stack__sample(ptq->thread, ptq->cpu, ptq->chain,
pt->synth_opts.callchain_sz + 1,
sample->ip, pt->kernel_start);
sample->callchain = ptq->chain;
@@ -1526,11 +1526,11 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
return 0;
if (pt->synth_opts.callchain || pt->synth_opts.thread_stack)
thread_stack__event(ptq->thread, ptq->flags, state->from_ip,
thread_stack__event(ptq->thread, ptq->cpu, ptq->flags, state->from_ip,
state->to_ip, ptq->insn_len,
state->trace_nr);
else
thread_stack__set_trace_nr(ptq->thread, state->trace_nr);
thread_stack__set_trace_nr(ptq->thread, ptq->cpu, state->trace_nr);
if (pt->sample_branches) {
err = intel_pt_synth_branch_sample(ptq);