linux-kernel - [PATCH 2/2] perf intel-pt: Fix CYC timestamps after standalone CBR

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Message-Id: <20230403154831.8651-3-adrian.hunter@intel.com>
Date:   Mon,  3 Apr 2023 18:48:31 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org
Subject: [PATCH 2/2] perf intel-pt: Fix CYC timestamps after standalone CBR

After a standalone CBR (not associated with TSC), update the cycles
reference timestamp and reset the cycle count, so that CYC timestamps are
calculated relative to that point with the new frequency.

Fixes: cc33618619ce ("perf tools: Add Intel PT support for decoding CYC packets")
Cc: stable@...r.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 0ac860c8dd2b..7145c5890de0 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -1998,6 +1998,8 @@ static void intel_pt_calc_cbr(struct intel_pt_decoder *decoder)
 
 	decoder->cbr = cbr;
 	decoder->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
+	decoder->cyc_ref_timestamp = decoder->timestamp;
+	decoder->cycle_cnt = 0;
 
 	intel_pt_mtc_cyc_cnt_cbr(decoder);
 }
-- 
2.34.1