perf intel-pt: Add support for efficient time interval filtering

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>

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 3e3a013..43ddc78 100644 (file)
--- 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 @@ err_free_queues:
 err_free:
        addr_filters__exit(&pt->filts);
        zfree(&pt->filter);
+       zfree(&pt->time_ranges);
        free(pt);
        return err;
 }