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Subject[PATCH 11/19] perf intel-pt: Add support for efficient time interval filtering
Date
Set up time ranges for efficient time interval filtering using the new
"fast forward" facility.

Because decoding is done in time order, intel_pt_time_filter() needs to
look only at the next start or end timestamp - refer intel_pt_next_time().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/intel-pt.c | 208 +++++++++++++++++++++++++++++++++++++
1 file changed, 208 insertions(+)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 3e3a01318b76..43ddc78a066e 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -42,6 +42,7 @@
#include "tsc.h"
#include "intel-pt.h"
#include "config.h"
+#include "time-utils.h"

#include "intel-pt-decoder/intel-pt-log.h"
#include "intel-pt-decoder/intel-pt-decoder.h"
@@ -50,6 +51,11 @@

#define MAX_TIMESTAMP (~0ULL)

+struct range {
+ u64 start;
+ u64 end;
+};
+
struct intel_pt {
struct auxtrace auxtrace;
struct auxtrace_queues queues;
@@ -118,6 +124,9 @@ struct intel_pt {

char *filter;
struct addr_filters filts;
+
+ struct range *time_ranges;
+ unsigned int range_cnt;
};

enum switch_state {
@@ -154,6 +163,9 @@ struct intel_pt_queue {
bool have_sample;
u64 time;
u64 timestamp;
+ u64 sel_timestamp;
+ bool sel_start;
+ unsigned int sel_idx;
u32 flags;
u16 insn_len;
u64 last_insn_cnt;
@@ -1007,6 +1019,23 @@ static void intel_pt_sample_flags(struct intel_pt_queue *ptq)
ptq->flags |= PERF_IP_FLAG_TRACE_END;
}

+static void intel_pt_setup_time_range(struct intel_pt *pt,
+ struct intel_pt_queue *ptq)
+{
+ if (!pt->range_cnt)
+ return;
+
+ ptq->sel_timestamp = pt->time_ranges[0].start;
+ ptq->sel_idx = 0;
+
+ if (ptq->sel_timestamp) {
+ ptq->sel_start = true;
+ } else {
+ ptq->sel_timestamp = pt->time_ranges[0].end;
+ ptq->sel_start = false;
+ }
+}
+
static int intel_pt_setup_queue(struct intel_pt *pt,
struct auxtrace_queue *queue,
unsigned int queue_nr)
@@ -1031,6 +1060,8 @@ static int intel_pt_setup_queue(struct intel_pt *pt,
ptq->step_through_buffers = true;

ptq->sync_switch = pt->sync_switch;
+
+ intel_pt_setup_time_range(pt, ptq);
}

if (!ptq->on_heap &&
@@ -1045,6 +1076,14 @@ static int intel_pt_setup_queue(struct intel_pt *pt,
intel_pt_log("queue %u getting timestamp\n", queue_nr);
intel_pt_log("queue %u decoding cpu %d pid %d tid %d\n",
queue_nr, ptq->cpu, ptq->pid, ptq->tid);
+
+ if (ptq->sel_start && ptq->sel_timestamp) {
+ ret = intel_pt_fast_forward(ptq->decoder,
+ ptq->sel_timestamp);
+ if (ret)
+ return ret;
+ }
+
while (1) {
state = intel_pt_decode(ptq->decoder);
if (state->err) {
@@ -1064,6 +1103,9 @@ static int intel_pt_setup_queue(struct intel_pt *pt,
queue_nr, ptq->timestamp);
ptq->state = state;
ptq->have_sample = true;
+ if (ptq->sel_start && ptq->sel_timestamp &&
+ ptq->timestamp < ptq->sel_timestamp)
+ ptq->have_sample = false;
intel_pt_sample_flags(ptq);
ret = auxtrace_heap__add(&pt->heap, queue_nr, ptq->timestamp);
if (ret)
@@ -1750,10 +1792,83 @@ static void intel_pt_enable_sync_switch(struct intel_pt *pt)
}
}

+/*
+ * To filter against time ranges, it is only necessary to look at the next start
+ * or end time.
+ */
+static bool intel_pt_next_time(struct intel_pt_queue *ptq)
+{
+ struct intel_pt *pt = ptq->pt;
+
+ if (ptq->sel_start) {
+ /* Next time is an end time */
+ ptq->sel_start = false;
+ ptq->sel_timestamp = pt->time_ranges[ptq->sel_idx].end;
+ return true;
+ } else if (ptq->sel_idx + 1 < pt->range_cnt) {
+ /* Next time is a start time */
+ ptq->sel_start = true;
+ ptq->sel_idx += 1;
+ ptq->sel_timestamp = pt->time_ranges[ptq->sel_idx].start;
+ return true;
+ }
+
+ /* No next time */
+ return false;
+}
+
+static int intel_pt_time_filter(struct intel_pt_queue *ptq, u64 *ff_timestamp)
+{
+ int err;
+
+ while (1) {
+ if (ptq->sel_start) {
+ if (ptq->timestamp >= ptq->sel_timestamp) {
+ /* After start time, so consider next time */
+ intel_pt_next_time(ptq);
+ if (!ptq->sel_timestamp) {
+ /* No end time */
+ return 0;
+ }
+ /* Check against end time */
+ continue;
+ }
+ /* Before start time, so fast forward */
+ ptq->have_sample = false;
+ if (ptq->sel_timestamp > *ff_timestamp) {
+ if (ptq->sync_switch) {
+ intel_pt_next_tid(ptq->pt, ptq);
+ ptq->switch_state = INTEL_PT_SS_UNKNOWN;
+ }
+ *ff_timestamp = ptq->sel_timestamp;
+ err = intel_pt_fast_forward(ptq->decoder,
+ ptq->sel_timestamp);
+ if (err)
+ return err;
+ }
+ return 0;
+ } else if (ptq->timestamp > ptq->sel_timestamp) {
+ /* After end time, so consider next time */
+ if (!intel_pt_next_time(ptq)) {
+ /* No next time range, so stop decoding */
+ ptq->have_sample = false;
+ ptq->switch_state = INTEL_PT_SS_NOT_TRACING;
+ return 1;
+ }
+ /* Check against next start time */
+ continue;
+ } else {
+ /* Before end time */
+ return 0;
+ }
+ }
+}
+
static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
{
const struct intel_pt_state *state = ptq->state;
struct intel_pt *pt = ptq->pt;
+ u64 ff_timestamp = 0;
int err;

if (!pt->kernel_start) {
@@ -1818,6 +1933,12 @@ static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
ptq->timestamp = state->timestamp;
}

+ if (ptq->sel_timestamp) {
+ err = intel_pt_time_filter(ptq, &ff_timestamp);
+ if (err)
+ return err;
+ }
+
if (!pt->timeless_decoding && ptq->timestamp >= *timestamp) {
*timestamp = ptq->timestamp;
return 0;
@@ -2223,6 +2344,7 @@ static void intel_pt_free(struct perf_session *session)
thread__put(pt->unknown_thread);
addr_filters__exit(&pt->filts);
zfree(&pt->filter);
+ zfree(&pt->time_ranges);
free(pt);
}

@@ -2520,6 +2642,85 @@ static int intel_pt_perf_config(const char *var, const char *value, void *data)
return 0;
}

+/* Find least TSC which converts to ns or later */
+static u64 intel_pt_tsc_start(u64 ns, struct intel_pt *pt)
+{
+ u64 tsc, tm;
+
+ tsc = perf_time_to_tsc(ns, &pt->tc);
+
+ while (1) {
+ tm = tsc_to_perf_time(tsc, &pt->tc);
+ if (tm < ns)
+ break;
+ tsc -= 1;
+ }
+
+ while (tm < ns)
+ tm = tsc_to_perf_time(++tsc, &pt->tc);
+
+ return tsc;
+}
+
+/* Find greatest TSC which converts to ns or earlier */
+static u64 intel_pt_tsc_end(u64 ns, struct intel_pt *pt)
+{
+ u64 tsc, tm;
+
+ tsc = perf_time_to_tsc(ns, &pt->tc);
+
+ while (1) {
+ tm = tsc_to_perf_time(tsc, &pt->tc);
+ if (tm > ns)
+ break;
+ tsc += 1;
+ }
+
+ while (tm > ns)
+ tm = tsc_to_perf_time(--tsc, &pt->tc);
+
+ return tsc;
+}
+
+static int intel_pt_setup_time_ranges(struct intel_pt *pt,
+ struct itrace_synth_opts *opts)
+{
+ struct perf_time_interval *p = opts->ptime_range;
+ int n = opts->range_num;
+ int i;
+
+ if (!n || !p || pt->timeless_decoding)
+ return 0;
+
+ pt->time_ranges = calloc(n, sizeof(struct range));
+ if (!pt->time_ranges)
+ return -ENOMEM;
+
+ pt->range_cnt = n;
+
+ intel_pt_log("%s: %u range(s)\n", __func__, n);
+
+ for (i = 0; i < n; i++) {
+ struct range *r = &pt->time_ranges[i];
+ u64 ts = p[i].start;
+ u64 te = p[i].end;
+
+ /*
+ * Take care to ensure the TSC range matches the perf-time range
+ * when converted back to perf-time.
+ */
+ r->start = ts ? intel_pt_tsc_start(ts, pt) : 0;
+ r->end = te ? intel_pt_tsc_end(te, pt) : 0;
+
+ intel_pt_log("range %d: perf time interval: %"PRIu64" to %"PRIu64"\n",
+ i, ts, te);
+ intel_pt_log("range %d: TSC time interval: %#"PRIx64" to %#"PRIx64"\n",
+ i, r->start, r->end);
+ }
+
+ return 0;
+}
+
static const char * const intel_pt_info_fmts[] = {
[INTEL_PT_PMU_TYPE] = " PMU Type %"PRId64"\n",
[INTEL_PT_TIME_SHIFT] = " Time Shift %"PRIu64"\n",
@@ -2752,6 +2953,12 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
pt->cbr2khz = tsc_freq / pt->max_non_turbo_ratio / 1000;
}

+ if (session->itrace_synth_opts) {
+ err = intel_pt_setup_time_ranges(pt, session->itrace_synth_opts);
+ if (err)
+ goto err_delete_thread;
+ }
+
if (pt->synth_opts.calls)
pt->branches_filter |= PERF_IP_FLAG_CALL | PERF_IP_FLAG_ASYNC |
PERF_IP_FLAG_TRACE_END;
@@ -2792,6 +2999,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
err_free:
addr_filters__exit(&pt->filts);
zfree(&pt->filter);
+ zfree(&pt->time_ranges);
free(pt);
return err;
}
--
2.17.1
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