[PATCH v5 1/5] perf arm-spe: Save clock parameters from TIME_CONV event

From: Leo Yan
Date: Wed May 19 2021 - 03:19:56 EST


During the recording phase, "perf record" tool synthesizes event
PERF_RECORD_TIME_CONV for the hardware clock parameters and saves the
event into the data file.

Afterwards, when processing the data file, the event TIME_CONV will be
processed at the very early time and is stored into session context.

This patch extracts these parameters from the session context and saves
into the structure "spe->tc" with the type perf_tsc_conversion, so that
the parameters are ready for conversion between clock counter and time
stamp.

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
---
tools/perf/util/arm-spe.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index 2539d4baec44..d2ae5a5c13ee 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -26,6 +26,7 @@
#include "symbol.h"
#include "thread.h"
#include "thread-stack.h"
+#include "tsc.h"
#include "tool.h"
#include "util/synthetic-events.h"

@@ -45,6 +46,8 @@ struct arm_spe {
struct machine *machine;
u32 pmu_type;

+ struct perf_tsc_conversion tc;
+
u8 timeless_decoding;
u8 data_queued;

@@ -1006,6 +1009,7 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
{
struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
size_t min_sz = sizeof(u64) * ARM_SPE_AUXTRACE_PRIV_MAX;
+ struct perf_record_time_conv *tc = &session->time_conv;
struct arm_spe *spe;
int err;

@@ -1027,6 +1031,28 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
spe->pmu_type = auxtrace_info->priv[ARM_SPE_PMU_TYPE];

spe->timeless_decoding = arm_spe__is_timeless_decoding(spe);
+
+ /*
+ * The synthesized event PERF_RECORD_TIME_CONV has been handled ahead
+ * and the parameters for hardware clock are stored in the session
+ * context. Passes these parameters to the struct perf_tsc_conversion
+ * in "spe->tc", which is used for later conversion between clock
+ * counter and timestamp.
+ *
+ * For backward compatibility, copies the fields starting from
+ * "time_cycles" only if they are contained in the event.
+ */
+ spe->tc.time_shift = tc->time_shift;
+ spe->tc.time_mult = tc->time_mult;
+ spe->tc.time_zero = tc->time_zero;
+
+ if (event_contains(*tc, time_cycles)) {
+ spe->tc.time_cycles = tc->time_cycles;
+ spe->tc.time_mask = tc->time_mask;
+ spe->tc.cap_user_time_zero = tc->cap_user_time_zero;
+ spe->tc.cap_user_time_short = tc->cap_user_time_short;
+ }
+
spe->auxtrace.process_event = arm_spe_process_event;
spe->auxtrace.process_auxtrace_event = arm_spe_process_auxtrace_event;
spe->auxtrace.flush_events = arm_spe_flush;
--
2.25.1