This patch set is to enable timestamp for Arm SPE trace. It reads out
TSC parameters from the TIME_CONV event, the parameters are used for
conversion between timer counter and kernel time and which is applied
for Arm SPE samples.
This version dropped the change for adding hardware clock parameters
into auxtrace info, alternatively, it utilizes the TIME_CONV event to
extract the clock parameters which is used for timestamp calculation.
This patch set can be clearly applied on perf/core branch with:
commit 2c0cb9f56020 ("perf test: Add a shell test for 'perf stat --bpf-counters' new option")
Ths patch series has been tested on Hisilicon D06 platform.
Changes from v2:
* Changed to use TIME_CONV event for extracing clock parameters (Al).
Changes from v1:
* Rebased patch series on the latest perf/core branch;
* Fixed the patch for dumping TSC parameters to support both the
older and new auxtrace info format.
Leo Yan (6):
perf arm-spe: Remove unused enum value ARM_SPE_PER_CPU_MMAPS
perf arm-spe: Save clock parameters from TIME_CONV event
perf arm-spe: Convert event kernel time to counter value
perf arm-spe: Assign kernel time to synthesized event
perf arm-spe: Bail out if the trace is later than perf event
perf arm-spe: Don't wait for PERF_RECORD_EXIT event
tools/perf/util/arm-spe.c | 66 +++++++++++++++++++++++++++++++++------
tools/perf/util/arm-spe.h | 1 -
2 files changed, 56 insertions(+), 11 deletions(-)
--
2.25.1
In current code, it assigns the arch timer counter to the synthesized
samples Arm SPE trace, thus the samples don't contain the kernel time
but only contain the raw counter value.
To fix the issue, this patch converts the timer counter to kernel time
and assigns it to sample timestamp.
Signed-off-by: Leo Yan <[email protected]>
---
tools/perf/util/arm-spe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index f66e10c62473..ec7df83b50fd 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -234,7 +234,7 @@ static void arm_spe_prep_sample(struct arm_spe *spe,
struct arm_spe_record *record = &speq->decoder->record;
if (!spe->timeless_decoding)
- sample->time = speq->timestamp;
+ sample->time = tsc_to_perf_time(record->timestamp, &spe->tc);
sample->ip = record->from_ip;
sample->cpumode = arm_spe_cpumode(spe, sample->ip);
--
2.25.1
It's possible that record in Arm SPE trace is later than perf event and
vice versa. This asks to correlate the perf events and Arm SPE
synthesized events to be processed in the manner of correct timing.
To achieve the time ordering, this patch reverses the flow, it firstly
calls arm_spe_sample() and then calls arm_spe_decode(). By comparing
the timestamp value and detect the perf event is coming earlier than Arm
SPE trace data, it bails out from the decoding loop, the last record is
pushed into auxtrace stack and is deferred to generate sample. To track
the timestamp, everytime it updates timestamp for the latest record.
Signed-off-by: Leo Yan <[email protected]>
---
tools/perf/util/arm-spe.c | 37 ++++++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index ec7df83b50fd..8facda81a06c 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -434,12 +434,36 @@ static int arm_spe_sample(struct arm_spe_queue *speq)
static int arm_spe_run_decoder(struct arm_spe_queue *speq, u64 *timestamp)
{
struct arm_spe *spe = speq->spe;
+ struct arm_spe_record *record;
int ret;
if (!spe->kernel_start)
spe->kernel_start = machine__kernel_start(spe->machine);
while (1) {
+ /*
+ * The usual logic is firstly to decode the packets, and then
+ * based the record to synthesize sample; but here the flow is
+ * reversed: it calls arm_spe_sample() for synthesizing samples
+ * prior to arm_spe_decode().
+ *
+ * Two reasons for this code logic:
+ * 1. Firstly, when setup queue in arm_spe__setup_queue(), it
+ * has decoded trace data and generated a record, but the record
+ * is left to generate sample until run to here, so it's correct
+ * to synthesize sample for the left record.
+ * 2. After decoding trace data, it needs to compare the record
+ * timestamp with the coming perf event, if the record timestamp
+ * is later than the perf event, it needs bail out and pushs the
+ * record into auxtrace heap, thus the record can be deferred to
+ * synthesize sample until run to here at the next time; so this
+ * can correlate samples between Arm SPE trace data and other
+ * perf events with correct time ordering.
+ */
+ ret = arm_spe_sample(speq);
+ if (ret)
+ return ret;
+
ret = arm_spe_decode(speq->decoder);
if (!ret) {
pr_debug("No data or all data has been processed.\n");
@@ -453,10 +477,17 @@ static int arm_spe_run_decoder(struct arm_spe_queue *speq, u64 *timestamp)
if (ret < 0)
continue;
- ret = arm_spe_sample(speq);
- if (ret)
- return ret;
+ record = &speq->decoder->record;
+ /* Update timestamp for the last record */
+ if (record->timestamp > speq->timestamp)
+ speq->timestamp = record->timestamp;
+
+ /*
+ * If the timestamp of the queue is later than timestamp of the
+ * coming perf event, bail out so can allow the perf event to
+ * be processed ahead.
+ */
if (!spe->timeless_decoding && speq->timestamp >= *timestamp) {
*timestamp = speq->timestamp;
return 0;
--
2.25.1
When decode Arm SPE trace, it waits for PERF_RECORD_EXIT event (the last
perf event) for processing trace data, which is needless and even might
cause logic error, e.g. it might fail to correlate perf events with Arm
SPE events correctly.
So this patch removes the condition checking for PERF_RECORD_EXIT event.
Signed-off-by: Leo Yan <[email protected]>
---
tools/perf/util/arm-spe.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index 8facda81a06c..5e98a29fcbdb 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -717,11 +717,7 @@ static int arm_spe_process_event(struct perf_session *session,
sample->time);
}
} else if (timestamp) {
- if (event->header.type == PERF_RECORD_EXIT) {
- err = arm_spe_process_queues(spe, timestamp);
- if (err)
- return err;
- }
+ err = arm_spe_process_queues(spe, timestamp);
}
return err;
--
2.25.1