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Subject[PATCH 3/4] perf intel-pt: Fix IPC with CYC threshold
Date
The code assumed every CYC-eligible packet has a CYC packet, which is not
the case when CYC thresholds are used. Fix by checking if a CYC packet is
actually present in that case.

Fixes: 5b1dc0fd1da06 ("perf intel-pt: Add support for samples to contain IPC ratio")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
.../util/intel-pt-decoder/intel-pt-decoder.c | 27 +++++++++++++++++++
.../util/intel-pt-decoder/intel-pt-decoder.h | 1 +
tools/perf/util/intel-pt.c | 13 +++++++++
3 files changed, 41 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 ef29f6b25e60..197eb58a39cb 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -24,6 +24,13 @@
#include "intel-pt-decoder.h"
#include "intel-pt-log.h"

+#define BITULL(x) (1ULL << (x))
+
+/* IA32_RTIT_CTL MSR bits */
+#define INTEL_PT_CYC_ENABLE BITULL(1)
+#define INTEL_PT_CYC_THRESHOLD (BITULL(22) | BITULL(21) | BITULL(20) | BITULL(19))
+#define INTEL_PT_CYC_THRESHOLD_SHIFT 19
+
#define INTEL_PT_BLK_SIZE 1024

#define BIT63 (((uint64_t)1 << 63))
@@ -167,6 +174,8 @@ struct intel_pt_decoder {
uint64_t sample_tot_cyc_cnt;
uint64_t base_cyc_cnt;
uint64_t cyc_cnt_timestamp;
+ uint64_t ctl;
+ uint64_t cyc_threshold;
double tsc_to_cyc;
bool continuous_period;
bool overflow;
@@ -204,6 +213,14 @@ static uint64_t intel_pt_lower_power_of_2(uint64_t x)
return x << i;
}

+static uint64_t intel_pt_cyc_threshold(uint64_t ctl)
+{
+ if (!(ctl & INTEL_PT_CYC_ENABLE))
+ return 0;
+
+ return (ctl & INTEL_PT_CYC_THRESHOLD) >> INTEL_PT_CYC_THRESHOLD_SHIFT;
+}
+
static void intel_pt_setup_period(struct intel_pt_decoder *decoder)
{
if (decoder->period_type == INTEL_PT_PERIOD_TICKS) {
@@ -245,12 +262,15 @@ struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)

decoder->flags = params->flags;

+ decoder->ctl = params->ctl;
decoder->period = params->period;
decoder->period_type = params->period_type;

decoder->max_non_turbo_ratio = params->max_non_turbo_ratio;
decoder->max_non_turbo_ratio_fp = params->max_non_turbo_ratio;

+ decoder->cyc_threshold = intel_pt_cyc_threshold(decoder->ctl);
+
intel_pt_setup_period(decoder);

decoder->mtc_shift = params->mtc_period;
@@ -2017,6 +2037,7 @@ static int intel_pt_hop_trace(struct intel_pt_decoder *decoder, bool *no_tip, in

static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
{
+ int last_packet_type = INTEL_PT_PAD;
bool no_tip = false;
int err;

@@ -2025,6 +2046,12 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
if (err)
return err;
next:
+ if (decoder->cyc_threshold) {
+ if (decoder->sample_cyc && last_packet_type != INTEL_PT_CYC)
+ decoder->sample_cyc = false;
+ last_packet_type = decoder->packet.type;
+ }
+
if (decoder->hop) {
switch (intel_pt_hop_trace(decoder, &no_tip, &err)) {
case HOP_IGNORE:
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
index b52937b03c8c..48adaa78acfc 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
@@ -244,6 +244,7 @@ struct intel_pt_params {
void *data;
bool return_compression;
bool branch_enable;
+ uint64_t ctl;
uint64_t period;
enum intel_pt_period_type period_type;
unsigned max_non_turbo_ratio;
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index d6d93ee03019..2fff6f760457 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -893,6 +893,18 @@ static bool intel_pt_sampling_mode(struct intel_pt *pt)
return false;
}

+static u64 intel_pt_ctl(struct intel_pt *pt)
+{
+ struct evsel *evsel;
+ u64 config;
+
+ evlist__for_each_entry(pt->session->evlist, evsel) {
+ if (intel_pt_get_config(pt, &evsel->core.attr, &config))
+ return config;
+ }
+ return 0;
+}
+
static u64 intel_pt_ns_to_ticks(const struct intel_pt *pt, u64 ns)
{
u64 quot, rem;
@@ -1026,6 +1038,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
params.data = ptq;
params.return_compression = intel_pt_return_compression(pt);
params.branch_enable = intel_pt_branch_enable(pt);
+ params.ctl = intel_pt_ctl(pt);
params.max_non_turbo_ratio = pt->max_non_turbo_ratio;
params.mtc_period = intel_pt_mtc_period(pt);
params.tsc_ctc_ratio_n = pt->tsc_ctc_ratio_n;
--
2.17.1
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