linux-kernel - [PATCH v4 4/6] perf tsc: Support cap_user_time_short for event TIME

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Date:   Mon, 14 Sep 2020 19:53:09 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Will Deacon <will@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kemeng Shi <shikemeng@...wei.com>,
        Ian Rogers <irogers@...gle.com>,
        Remi Bernon <rbernon@...eweavers.com>,
        Nick Gasson <nick.gasson@....com>,
        Stephane Eranian <eranian@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Steve MacLean <Steve.MacLean@...rosoft.com>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Zou Wei <zou_wei@...wei.com>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v4 4/6] perf tsc: Support cap_user_time_short for event TIME_CONV

The synthesized event TIME_CONV doesn't contain the complete parameters
for counters, this will lead to wrong conversion between counter cycles
and timestamp.

This patch extends event TIME_CONV to record flags 'cap_user_time_zero'
which is used to indicate the counter parameters are valid or not, if
not will directly return 0 for timestamp calculation.  And record the
flag 'cap_user_time_short' and its relevant fields 'time_cycles' and
'time_mask' for cycle calibration.

Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 tools/lib/perf/include/perf/event.h |  4 ++++
 tools/perf/util/jitdump.c           | 14 +++++++++-----
 tools/perf/util/tsc.c               |  4 ++++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index 842028858d66..a6dbba6b9073 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -324,6 +324,10 @@ struct perf_record_time_conv {
 	__u64			 time_shift;
 	__u64			 time_mult;
 	__u64			 time_zero;
+	__u64			 time_cycles;
+	__u64			 time_mask;
+	bool			 cap_user_time_zero;
+	bool			 cap_user_time_short;
 };
 
 struct perf_record_header_feature {
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index 0804308ef285..055bab7a92b3 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -374,11 +374,15 @@ static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
 	if (!jd->use_arch_timestamp)
 		return timestamp;
 
-	tc.time_shift = jd->session->time_conv.time_shift;
-	tc.time_mult  = jd->session->time_conv.time_mult;
-	tc.time_zero  = jd->session->time_conv.time_zero;
-
-	if (!tc.time_mult)
+	tc.time_shift	       = jd->session->time_conv.time_shift;
+	tc.time_mult	       = jd->session->time_conv.time_mult;
+	tc.time_zero	       = jd->session->time_conv.time_zero;
+	tc.time_cycles	       = jd->session->time_conv.time_cycles;
+	tc.time_mask	       = jd->session->time_conv.time_mask;
+	tc.cap_user_time_zero  = jd->session->time_conv.cap_user_time_zero;
+	tc.cap_user_time_short = jd->session->time_conv.cap_user_time_short;
+
+	if (!tc.cap_user_time_zero)
 		return 0;
 
 	return tsc_to_perf_time(timestamp, &tc);
diff --git a/tools/perf/util/tsc.c b/tools/perf/util/tsc.c
index c0ca40204649..62b4c75c966c 100644
--- a/tools/perf/util/tsc.c
+++ b/tools/perf/util/tsc.c
@@ -98,6 +98,10 @@ int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
 	event.time_conv.time_mult  = tc.time_mult;
 	event.time_conv.time_shift = tc.time_shift;
 	event.time_conv.time_zero  = tc.time_zero;
+	event.time_conv.time_cycles = tc.time_cycles;
+	event.time_conv.time_mask = tc.time_mask;
+	event.time_conv.cap_user_time_zero = tc.cap_user_time_zero;
+	event.time_conv.cap_user_time_short = tc.cap_user_time_short;
 
 	return process(tool, &event, NULL, machine);
 }
-- 
2.17.1