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Subject[PATCH 73/85] perf intel-pt: Add support for efficient time interval filtering
Date
From: Adrian Hunter <adrian.hunter@intel.com>

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>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190604130017.31207-12-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.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;
}
--
2.20.1
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