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Subject[PATCH V2 3/3] perf intel-pt: Add support for PERF_RECORD_AUX_OUTPUT_HW_ID
Date
Originally, software only supported redirecting at most one PEBS event to
Intel PT (PEBS-via-PT) because it was not able to differentiate one event
from another. To overcome that, add support for the
PERF_RECORD_AUX_OUTPUT_HW_ID side-band event.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
---
tools/perf/Documentation/perf-intel-pt.txt | 7 +-
tools/perf/util/intel-pt.c | 85 +++++++++++++++++++++-
2 files changed, 87 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
index bcf3eca5afbe..f3e9880614fd 100644
--- a/tools/perf/Documentation/perf-intel-pt.txt
+++ b/tools/perf/Documentation/perf-intel-pt.txt
@@ -1135,7 +1135,12 @@ Recording is selected by using the aux-output config term e.g.

perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}' uname

-Note that currently, software only supports redirecting at most one PEBS event.
+Originally, software only supported redirecting at most one PEBS event because it
+was not able to differentiate one event from another. To overcome that, more recent
+kernels and perf tools add support for the PERF_RECORD_AUX_OUTPUT_HW_ID side-band event.
+To check for the presence of that event in a PEBS-via-PT trace:
+
+ perf script -D --no-itrace | grep PERF_RECORD_AUX_OUTPUT_HW_ID

To display PEBS events from the Intel PT trace, use the itrace 'o' option e.g.

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 0dfec8761b9a..483b63217555 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -110,6 +110,7 @@ struct intel_pt {
u64 cbr_id;
u64 psb_id;

+ bool single_pebs;
bool sample_pebs;
struct evsel *pebs_evsel;

@@ -143,6 +144,14 @@ enum switch_state {
INTEL_PT_SS_EXPECTING_SWITCH_IP,
};

+/* applicable_counters is 64-bits */
+#define INTEL_PT_MAX_PEBS 64
+
+struct intel_pt_pebs_event {
+ struct evsel *evsel;
+ u64 id;
+};
+
struct intel_pt_queue {
struct intel_pt *pt;
unsigned int queue_nr;
@@ -184,6 +193,7 @@ struct intel_pt_queue {
u64 last_br_cyc_cnt;
unsigned int cbr_seen;
char insn[INTEL_PT_INSN_BUF_SZ];
+ struct intel_pt_pebs_event pebs[INTEL_PT_MAX_PEBS];
};

static void intel_pt_dump(struct intel_pt *pt __maybe_unused,
@@ -1873,15 +1883,13 @@ static void intel_pt_add_lbrs(struct branch_stack *br_stack,
}
}

-static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
+static int intel_pt_do_synth_pebs_sample(struct intel_pt_queue *ptq, struct evsel *evsel, u64 id)
{
const struct intel_pt_blk_items *items = &ptq->state->items;
struct perf_sample sample = { .ip = 0, };
union perf_event *event = ptq->event_buf;
struct intel_pt *pt = ptq->pt;
- struct evsel *evsel = pt->pebs_evsel;
u64 sample_type = evsel->core.attr.sample_type;
- u64 id = evsel->core.id[0];
u8 cpumode;
u64 regs[8 * sizeof(sample.intr_regs.mask)];

@@ -2007,6 +2015,45 @@ static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
return intel_pt_deliver_synth_event(pt, event, &sample, sample_type);
}

+static int intel_pt_synth_single_pebs_sample(struct intel_pt_queue *ptq)
+{
+ struct intel_pt *pt = ptq->pt;
+ struct evsel *evsel = pt->pebs_evsel;
+ u64 id = evsel->core.id[0];
+
+ return intel_pt_do_synth_pebs_sample(ptq, evsel, id);
+}
+
+static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
+{
+ const struct intel_pt_blk_items *items = &ptq->state->items;
+ struct intel_pt_pebs_event *pe;
+ struct intel_pt *pt = ptq->pt;
+ int err = -EINVAL;
+ int hw_id;
+
+ if (!items->has_applicable_counters || !items->applicable_counters) {
+ if (!pt->single_pebs)
+ pr_err("PEBS-via-PT record with no applicable_counters\n");
+ return intel_pt_synth_single_pebs_sample(ptq);
+ }
+
+ for_each_set_bit(hw_id, &items->applicable_counters, INTEL_PT_MAX_PEBS) {
+ pe = &ptq->pebs[hw_id];
+ if (!pe->evsel) {
+ if (!pt->single_pebs)
+ pr_err("PEBS-via-PT record with no matching event, hw_id %d\n",
+ hw_id);
+ return intel_pt_synth_single_pebs_sample(ptq);
+ }
+ err = intel_pt_do_synth_pebs_sample(ptq, pe->evsel, pe->id);
+ if (err)
+ return err;
+ }
+
+ return err;
+}
+
static int intel_pt_synth_error(struct intel_pt *pt, int code, int cpu,
pid_t pid, pid_t tid, u64 ip, u64 timestamp)
{
@@ -2777,6 +2824,30 @@ static int intel_pt_process_itrace_start(struct intel_pt *pt,
event->itrace_start.tid);
}

+static int intel_pt_process_aux_output_hw_id(struct intel_pt *pt,
+ union perf_event *event,
+ struct perf_sample *sample)
+{
+ u64 hw_id = event->aux_output_hw_id.hw_id;
+ struct auxtrace_queue *queue;
+ struct intel_pt_queue *ptq;
+ struct evsel *evsel;
+
+ queue = auxtrace_queues__sample_queue(&pt->queues, sample, pt->session);
+ evsel = evlist__id2evsel_strict(pt->session->evlist, sample->id);
+ if (!queue || !queue->priv || !evsel || hw_id > INTEL_PT_MAX_PEBS) {
+ pr_err("Bad AUX output hardware ID\n");
+ return -EINVAL;
+ }
+
+ ptq = queue->priv;
+
+ ptq->pebs[hw_id].evsel = evsel;
+ ptq->pebs[hw_id].id = sample->id;
+
+ return 0;
+}
+
static int intel_pt_find_map(struct thread *thread, u8 cpumode, u64 addr,
struct addr_location *al)
{
@@ -2902,6 +2973,8 @@ static int intel_pt_process_event(struct perf_session *session,
err = intel_pt_process_switch(pt, sample);
else if (event->header.type == PERF_RECORD_ITRACE_START)
err = intel_pt_process_itrace_start(pt, event, sample);
+ else if (event->header.type == PERF_RECORD_AUX_OUTPUT_HW_ID)
+ err = intel_pt_process_aux_output_hw_id(pt, event, sample);
else if (event->header.type == PERF_RECORD_SWITCH ||
event->header.type == PERF_RECORD_SWITCH_CPU_WIDE)
err = intel_pt_context_switch(pt, event, sample);
@@ -3285,9 +3358,13 @@ static void intel_pt_setup_pebs_events(struct intel_pt *pt)

evlist__for_each_entry(pt->session->evlist, evsel) {
if (evsel->core.attr.aux_output && evsel->core.id) {
+ if (pt->single_pebs) {
+ pt->single_pebs = false;
+ return;
+ }
+ pt->single_pebs = true;
pt->sample_pebs = true;
pt->pebs_evsel = evsel;
- return;
}
}
}
--
2.17.1
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