[PATCH 1/2] perf pt: Mark PT return events as "return"

From: Andi Kleen
Date: Fri May 20 2016 - 15:52:40 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

With perf script --itrace=cr we can synthesize calls and returns out of
a PT log. However both calls and returns are marked with the same event,
called branches. This makes it difficult to read and post process,
because calls and returns are somewhat diffferent.

Create a separate return event and mark the returns as return.

Cc: adrian.hunter@xxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
tools/perf/util/intel-pt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 48 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index ddec87f6e616..25f839e765ef 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -82,9 +82,12 @@ struct intel_pt {
u64 instructions_id;

bool sample_branches;
+ bool sample_returns;
u32 branches_filter;
u64 branches_sample_type;
+ u64 returns_sample_type;
u64 branches_id;
+ u64 returns_id;

bool sample_transactions;
u64 transactions_sample_type;
@@ -960,7 +963,8 @@ static int intel_pt_inject_event(union perf_event *event,
return perf_event__synthesize_sample(event, type, 0, sample, swapped);
}

-static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
+static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq,
+ bool is_return)
{
int ret;
struct intel_pt *pt = ptq->pt;
@@ -990,8 +994,13 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
sample.pid = ptq->pid;
sample.tid = ptq->tid;
sample.addr = ptq->state->to_ip;
- sample.id = ptq->pt->branches_id;
- sample.stream_id = ptq->pt->branches_id;
+ if (is_return) {
+ sample.id = ptq->pt->returns_id;
+ sample.stream_id = ptq->pt->returns_id;
+ } else {
+ sample.id = ptq->pt->branches_id;
+ sample.stream_id = ptq->pt->branches_id;
+ }
sample.period = 1;
sample.cpu = ptq->cpu;
sample.flags = ptq->flags;
@@ -1014,6 +1023,8 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)

if (pt->synth_opts.inject) {
ret = intel_pt_inject_event(event, &sample,
+ is_return ?
+ pt->returns_sample_type :
pt->branches_sample_type,
pt->synth_needs_swap);
if (ret)
@@ -1241,7 +1252,13 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
thread_stack__set_trace_nr(ptq->thread, state->trace_nr);

if (pt->sample_branches) {
- err = intel_pt_synth_branch_sample(ptq);
+ err = intel_pt_synth_branch_sample(ptq, false);
+ if (err)
+ return err;
+ }
+
+ if (pt->sample_returns) {
+ err = intel_pt_synth_branch_sample(ptq, true);
if (err)
return err;
}
@@ -1956,7 +1973,33 @@ static int intel_pt_synth_events(struct intel_pt *pt,
}
pt->sample_branches = true;
pt->branches_sample_type = attr.sample_type;
- pt->branches_id = id;
+ pt->branches_id = id++;
+ }
+ if (pt->synth_opts.returns) {
+ attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
+ attr.sample_period = 1;
+ attr.sample_type |= PERF_SAMPLE_ADDR;
+ attr.sample_type &= ~(u64)PERF_SAMPLE_CALLCHAIN;
+ attr.sample_type &= ~(u64)PERF_SAMPLE_BRANCH_STACK;
+ pr_debug("Synthesizing 'return' event with id %" PRIu64 " sample type %#" PRIx64 "\n",
+ id, (u64)attr.sample_type);
+ err = intel_pt_synth_event(session, &attr, id);
+ if (err) {
+ pr_err("%s: failed to synthesize 'return' event type\n",
+ __func__);
+ return err;
+ }
+ pt->sample_returns = true;
+ pt->returns_sample_type = attr.sample_type;
+ pt->returns_id = id;
+ evlist__for_each(evlist, evsel) {
+ if (evsel->id && evsel->id[0] == pt->returns_id) {
+ if (evsel->name)
+ zfree(&evsel->name);
+ evsel->name = strdup("return");
+ break;
+ }
+ }
}

pt->synth_needs_swap = evsel->needs_swap;
--
2.5.5