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Subject[PATCH 14/85] perf intel-pt: Accumulate cycle count from TSC/TMA/MTC packets
Date
From: Adrian Hunter <adrian.hunter@intel.com>

When CYC packets are not available, it is still possible to count cycles
using TSC/TMA/MTC timestamps.

As the timestamp increments in TSC ticks, convert to CPU cycles using
the current core-to-bus ratio.

Do not accumulate cycles when control flow packet generation is not
enabled, nor when time has been "lost", typically due to mwait, which is
indicated by a TSC/TMA packet that is not part of PSB+.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190520113728.14389-12-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
.../util/intel-pt-decoder/intel-pt-decoder.c | 51 +++++++++++++++++++
1 file changed, 51 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 99773445872d..9eb778f9c911 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -163,6 +163,9 @@ struct intel_pt_decoder {
uint64_t last_masked_timestamp;
uint64_t tot_cyc_cnt;
uint64_t sample_tot_cyc_cnt;
+ uint64_t base_cyc_cnt;
+ uint64_t cyc_cnt_timestamp;
+ double tsc_to_cyc;
bool continuous_period;
bool overflow;
bool set_fup_tx_flags;
@@ -1423,6 +1426,42 @@ static int intel_pt_overflow(struct intel_pt_decoder *decoder)
return -EOVERFLOW;
}

+static inline void intel_pt_mtc_cyc_cnt_pge(struct intel_pt_decoder *decoder)
+{
+ if (decoder->have_cyc)
+ return;
+
+ decoder->cyc_cnt_timestamp = decoder->timestamp;
+ decoder->base_cyc_cnt = decoder->tot_cyc_cnt;
+}
+
+static inline void intel_pt_mtc_cyc_cnt_cbr(struct intel_pt_decoder *decoder)
+{
+ decoder->tsc_to_cyc = decoder->cbr / decoder->max_non_turbo_ratio_fp;
+
+ if (decoder->pge)
+ intel_pt_mtc_cyc_cnt_pge(decoder);
+}
+
+static inline void intel_pt_mtc_cyc_cnt_upd(struct intel_pt_decoder *decoder)
+{
+ uint64_t tot_cyc_cnt, tsc_delta;
+
+ if (decoder->have_cyc)
+ return;
+
+ decoder->sample_cyc = true;
+
+ if (!decoder->pge || decoder->timestamp <= decoder->cyc_cnt_timestamp)
+ return;
+
+ tsc_delta = decoder->timestamp - decoder->cyc_cnt_timestamp;
+ tot_cyc_cnt = tsc_delta * decoder->tsc_to_cyc + decoder->base_cyc_cnt;
+
+ if (tot_cyc_cnt > decoder->tot_cyc_cnt)
+ decoder->tot_cyc_cnt = tot_cyc_cnt;
+}
+
static void intel_pt_calc_tma(struct intel_pt_decoder *decoder)
{
uint32_t ctc = decoder->packet.payload;
@@ -1432,6 +1471,11 @@ static void intel_pt_calc_tma(struct intel_pt_decoder *decoder)
if (!decoder->tsc_ctc_ratio_d)
return;

+ if (decoder->pge && !decoder->in_psb)
+ intel_pt_mtc_cyc_cnt_pge(decoder);
+ else
+ intel_pt_mtc_cyc_cnt_upd(decoder);
+
decoder->last_mtc = (ctc >> decoder->mtc_shift) & 0xff;
decoder->ctc_timestamp = decoder->tsc_timestamp - fc;
if (decoder->tsc_ctc_mult) {
@@ -1487,6 +1531,8 @@ static void intel_pt_calc_mtc_timestamp(struct intel_pt_decoder *decoder)
else
decoder->timestamp = timestamp;

+ intel_pt_mtc_cyc_cnt_upd(decoder);
+
decoder->timestamp_insn_cnt = 0;
decoder->last_mtc = mtc;

@@ -1511,6 +1557,8 @@ 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;
+
+ intel_pt_mtc_cyc_cnt_cbr(decoder);
}

static void intel_pt_calc_cyc_timestamp(struct intel_pt_decoder *decoder)
@@ -1706,6 +1754,7 @@ static int intel_pt_walk_fup_tip(struct intel_pt_decoder *decoder)
decoder->state.to_ip = decoder->ip;
}
decoder->state.type |= INTEL_PT_TRACE_BEGIN;
+ intel_pt_mtc_cyc_cnt_pge(decoder);
return 0;

case INTEL_PT_TIP:
@@ -1776,6 +1825,7 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)

case INTEL_PT_TIP_PGE: {
decoder->pge = true;
+ intel_pt_mtc_cyc_cnt_pge(decoder);
if (decoder->packet.count == 0) {
intel_pt_log_at("Skipping zero TIP.PGE",
decoder->pos);
@@ -2138,6 +2188,7 @@ static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)

case INTEL_PT_TIP_PGE:
decoder->pge = true;
+ intel_pt_mtc_cyc_cnt_pge(decoder);
if (intel_pt_have_ip(decoder))
intel_pt_set_ip(decoder);
if (!decoder->ip)
--
2.20.1
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