Hi Namhyung, thanks for your comments.

On 16/12/2021 01:18, Namhyung Kim wrote:

Hello,

On Wed, Dec 15, 2021 at 10:46 AM German Gomez [off-list ref] wrote:

quoted

Synthesize instruction events per every decoded ARM SPE record.

Because Arm SPE implements a hardware-based sample period, and perf
implements a software-based one that gets applied on top, also add a
warning to make the user aware.

Signed-off-by: German Gomez <redacted>
---
Changes since v1 [https://lore.kernel.org/all/20211117142833.226629-1-german.gomez@arm.com (local)]
  - Generate events with "--itrace=i" instead of "--itrace=o".
  - Generate events with virt_addr, phys_addr, and data_src values.
---
 tools/perf/util/arm-spe.c | 58 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index fccac06b573a..879583822c8f 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c

@@ -58,6 +58,8 @@ struct arm_spe {
        u8                              sample_branch;
        u8                              sample_remote_access;
        u8                              sample_memory;
+       u8                              sample_instructions;
+       u64                             instructions_sample_period;

        u64                             l1d_miss_id;
        u64                             l1d_access_id;

@@ -68,6 +70,7 @@ struct arm_spe {
        u64                             branch_miss_id;
        u64                             remote_access_id;
        u64                             memory_id;
+       u64                             instructions_id;

        u64                             kernel_start;

@@ -90,6 +93,7 @@ struct arm_spe_queue {
        u64                             time;
        u64                             timestamp;
        struct thread                   *thread;
+       u64                             period_instructions;
 };

 static void arm_spe_dump(struct arm_spe *spe __maybe_unused,

@@ -202,6 +206,7 @@ static struct arm_spe_queue *arm_spe__alloc_queue(struct arm_spe *spe,
        speq->pid = -1;
        speq->tid = -1;
        speq->cpu = -1;
+       speq->period_instructions = 0;

        /* params set */
        params.get_trace = arm_spe_get_trace;

@@ -351,6 +356,33 @@ static int arm_spe__synth_branch_sample(struct arm_spe_queue *speq,
        return arm_spe_deliver_synth_event(spe, speq, event, &sample);
 }

+static int arm_spe__synth_instruction_sample(struct arm_spe_queue *speq,
+                                            u64 spe_events_id, u64 data_src)
+{
+       struct arm_spe *spe = speq->spe;
+       struct arm_spe_record *record = &speq->decoder->record;
+       union perf_event *event = speq->event_buf;
+       struct perf_sample sample = { .ip = 0, };
+
+       /*
+        * Handles perf instruction sampling period.
+        */
+       speq->period_instructions++;
+       if (speq->period_instructions < spe->instructions_sample_period)
+               return 0;
+       speq->period_instructions = 0;
+
+       arm_spe_prep_sample(spe, speq, event, &sample);
+
+       sample.id = spe_events_id;
+       sample.stream_id = spe_events_id;
+       sample.addr = record->virt_addr;
+       sample.phys_addr = record->phys_addr;
+       sample.data_src = data_src;

I think it should set sample.period to spe->instructions_sample_period.

Ack!

Also it can set sample.weight but I think we lost my patch

I forgot to apply your latency patch first. I will add it.

Thanks,
German

  https://lore.kernel.org/r/20211201220855.1260688-1-namhyung@kernel.org (local)

Arnaldo, can you please take a look?

quoted

+
+       return arm_spe_deliver_synth_event(spe, speq, event, &sample);
+}
+
 #define SPE_MEM_TYPE   (ARM_SPE_L1D_ACCESS | ARM_SPE_L1D_MISS | \
                         ARM_SPE_LLC_ACCESS | ARM_SPE_LLC_MISS | \
                         ARM_SPE_REMOTE_ACCESS)

@@ -480,6 +512,12 @@ static int arm_spe_sample(struct arm_spe_queue *speq)
                        return err;
        }

+       if (spe->sample_instructions) {
+               err = arm_spe__synth_instruction_sample(speq, spe->instructions_id, data_src);
+               if (err)
+                       return err;
+       }
+
        return 0;
 }

@@ -1107,6 +1145,26 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
                        return err;
                spe->memory_id = id;
                arm_spe_set_event_name(evlist, id, "memory");
+               id += 1;
+       }
+
+       if (spe->synth_opts.instructions) {
+               if (spe->synth_opts.period_type != PERF_ITRACE_PERIOD_INSTRUCTIONS)
+                       return -EINVAL;
+
+               if (spe->synth_opts.period > 1)
+                       pr_warning("Arm SPE has a hardware-based sample period.\n"
+                                  "More instruction events will be discarded by --itrace\n");
+
+               spe->sample_instructions = true;
+               attr.config = PERF_COUNT_HW_INSTRUCTIONS;
+               attr.sample_period = spe->synth_opts.period;
+               spe->instructions_sample_period = attr.sample_period;
+               err = arm_spe_synth_event(session, &attr, id);
+               if (err)
+                       return err;
+               spe->instructions_id = id;
+               arm_spe_set_event_name(evlist, id, "instructions");

Yeah, I think it's a better name than "all". :)

Thanks,
Namhyung

quoted

        }

        return 0;
--
2.25.1

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