stat.c

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// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <inttypes.h>
#include <math.h>
#include "stat.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"

void update_stats(struct stats *stats, u64 val)
{
    double delta;

    stats->n++;
    delta = val - stats->mean;
    stats->mean += delta / stats->n;
    stats->M2 += delta*(val - stats->mean);

    if (val > stats->max)
        stats->max = val;

    if (val < stats->min)
        stats->min = val;
}

double avg_stats(struct stats *stats)
{
    return stats->mean;
}

/*
 * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
 *
 *       (\Sum n_i^2) - ((\Sum n_i)^2)/n
 * s^2 = -------------------------------
 *                  n - 1
 *
 * http://en.wikipedia.org/wiki/Stddev
 *
 * The std dev of the mean is related to the std dev by:
 *
 *             s
 * s_mean = -------
 *          sqrt(n)
 *
 */
double stddev_stats(struct stats *stats)
{
    double variance, variance_mean;

    if (stats->n < 2)
        return 0.0;

    variance = stats->M2 / (stats->n - 1);
    variance_mean = variance / stats->n;

    return sqrt(variance_mean);
}

double rel_stddev_stats(double stddev, double avg)
{
    double pct = 0.0;

    if (avg)
        pct = 100.0 * stddev/avg;

    return pct;
}

bool __perf_evsel_stat__is(struct perf_evsel *evsel,
               enum perf_stat_evsel_id id)
{
    struct perf_stat_evsel *ps = evsel->stats;

    return ps->id == id;
}

#define ID(id, name) [PERF_STAT_EVSEL_ID__##id] = #name
static const char *id_str[PERF_STAT_EVSEL_ID__MAX] = {
    ID(NONE,        x),
    ID(CYCLES_IN_TX,    cpu/cycles-t/),
    ID(TRANSACTION_START,   cpu/tx-start/),
    ID(ELISION_START,   cpu/el-start/),
    ID(CYCLES_IN_TX_CP, cpu/cycles-ct/),
    ID(TOPDOWN_TOTAL_SLOTS, topdown-total-slots),
    ID(TOPDOWN_SLOTS_ISSUED, topdown-slots-issued),
    ID(TOPDOWN_SLOTS_RETIRED, topdown-slots-retired),
    ID(TOPDOWN_FETCH_BUBBLES, topdown-fetch-bubbles),
    ID(TOPDOWN_RECOVERY_BUBBLES, topdown-recovery-bubbles),
    ID(SMI_NUM, msr/smi/),
    ID(APERF, msr/aperf/),
};
#undef ID

static void perf_stat_evsel_id_init(struct perf_evsel *evsel)
{
    struct perf_stat_evsel *ps = evsel->stats;
    int i;

    /* ps->id is 0 hence PERF_STAT_EVSEL_ID__NONE by default */

    for (i = 0; i < PERF_STAT_EVSEL_ID__MAX; i++) {
        if (!strcmp(perf_evsel__name(evsel), id_str[i])) {
            ps->id = i;
            break;
        }
    }
}

static void perf_evsel__reset_stat_priv(struct perf_evsel *evsel)
{
    int i;
    struct perf_stat_evsel *ps = evsel->stats;

    for (i = 0; i < 3; i++)
        init_stats(&ps->res_stats[i]);

    perf_stat_evsel_id_init(evsel);
}

static int perf_evsel__alloc_stat_priv(struct perf_evsel *evsel)
{
    evsel->stats = zalloc(sizeof(struct perf_stat_evsel));
    if (evsel->stats == NULL)
        return -ENOMEM;
    perf_evsel__reset_stat_priv(evsel);
    return 0;
}

static void perf_evsel__free_stat_priv(struct perf_evsel *evsel)
{
    struct perf_stat_evsel *ps = evsel->stats;

    if (ps)
        free(ps->group_data);
    zfree(&evsel->stats);
}

static int perf_evsel__alloc_prev_raw_counts(struct perf_evsel *evsel,
                         int ncpus, int nthreads)
{
    struct perf_counts *counts;

    counts = perf_counts__new(ncpus, nthreads);
    if (counts)
        evsel->prev_raw_counts = counts;

    return counts ? 0 : -ENOMEM;
}

static void perf_evsel__free_prev_raw_counts(struct perf_evsel *evsel)
{
    perf_counts__delete(evsel->prev_raw_counts);
    evsel->prev_raw_counts = NULL;
}

static int perf_evsel__alloc_stats(struct perf_evsel *evsel, bool alloc_raw)
{
    int ncpus = perf_evsel__nr_cpus(evsel);
    int nthreads = thread_map__nr(evsel->threads);

    if (perf_evsel__alloc_stat_priv(evsel) < 0 ||
        perf_evsel__alloc_counts(evsel, ncpus, nthreads) < 0 ||
        (alloc_raw && perf_evsel__alloc_prev_raw_counts(evsel, ncpus, nthreads) < 0))
        return -ENOMEM;

    return 0;
}

int perf_evlist__alloc_stats(struct perf_evlist *evlist, bool alloc_raw)
{
    struct perf_evsel *evsel;

    evlist__for_each_entry(evlist, evsel) {
        if (perf_evsel__alloc_stats(evsel, alloc_raw))
            goto out_free;
    }

    return 0;

out_free:
    perf_evlist__free_stats(evlist);
    return -1;
}

void perf_evlist__free_stats(struct perf_evlist *evlist)
{
    struct perf_evsel *evsel;

    evlist__for_each_entry(evlist, evsel) {
        perf_evsel__free_stat_priv(evsel);
        perf_evsel__free_counts(evsel);
        perf_evsel__free_prev_raw_counts(evsel);
    }
}

void perf_evlist__reset_stats(struct perf_evlist *evlist)
{
    struct perf_evsel *evsel;

    evlist__for_each_entry(evlist, evsel) {
        perf_evsel__reset_stat_priv(evsel);
        perf_evsel__reset_counts(evsel);
    }
}

static void zero_per_pkg(struct perf_evsel *counter)
{
    if (counter->per_pkg_mask)
        memset(counter->per_pkg_mask, 0, MAX_NR_CPUS);
}

static int check_per_pkg(struct perf_evsel *counter,
             struct perf_counts_values *vals, int cpu, bool *skip)
{
    unsigned long *mask = counter->per_pkg_mask;
    struct cpu_map *cpus = perf_evsel__cpus(counter);
    int s;

    *skip = false;

    if (!counter->per_pkg)
        return 0;

    if (cpu_map__empty(cpus))
        return 0;

    if (!mask) {
        mask = zalloc(MAX_NR_CPUS);
        if (!mask)
            return -ENOMEM;

        counter->per_pkg_mask = mask;
    }

    /*
     * we do not consider an event that has not run as a good
     * instance to mark a package as used (skip=1). Otherwise
     * we may run into a situation where the first CPU in a package
     * is not running anything, yet the second is, and this function
     * would mark the package as used after the first CPU and would
     * not read the values from the second CPU.
     */
    if (!(vals->run && vals->ena))
        return 0;

    s = cpu_map__get_socket(cpus, cpu, NULL);
    if (s < 0)
        return -1;

    *skip = test_and_set_bit(s, mask) == 1;
    return 0;
}

static int
process_counter_values(struct perf_stat_config *config, struct perf_evsel *evsel,
               int cpu, int thread,
               struct perf_counts_values *count)
{
    struct perf_counts_values *aggr = &evsel->counts->aggr;
    static struct perf_counts_values zero;
    bool skip = false;

    if (check_per_pkg(evsel, count, cpu, &skip)) {
        pr_err("failed to read per-pkg counter\n");
        return -1;
    }

    if (skip)
        count = &zero;

    switch (config->aggr_mode) {
    case AGGR_THREAD:
    case AGGR_CORE:
    case AGGR_SOCKET:
    case AGGR_NONE:
        if (!evsel->snapshot)
            perf_evsel__compute_deltas(evsel, cpu, thread, count);
        perf_counts_values__scale(count, config->scale, NULL);
        if (config->aggr_mode == AGGR_NONE)
            perf_stat__update_shadow_stats(evsel, count->val, cpu,
                               &rt_stat);
        if (config->aggr_mode == AGGR_THREAD) {
            if (config->stats)
                perf_stat__update_shadow_stats(evsel,
                    count->val, 0, &config->stats[thread]);
            else
                perf_stat__update_shadow_stats(evsel,
                    count->val, 0, &rt_stat);
        }
        break;
    case AGGR_GLOBAL:
        aggr->val += count->val;
        if (config->scale) {
            aggr->ena += count->ena;
            aggr->run += count->run;
        }
    case AGGR_UNSET:
    default:
        break;
    }

    return 0;
}

static int process_counter_maps(struct perf_stat_config *config,
                struct perf_evsel *counter)
{
    int nthreads = thread_map__nr(counter->threads);
    int ncpus = perf_evsel__nr_cpus(counter);
    int cpu, thread;

    if (counter->system_wide)
        nthreads = 1;

    for (thread = 0; thread < nthreads; thread++) {
        for (cpu = 0; cpu < ncpus; cpu++) {
            if (process_counter_values(config, counter, cpu, thread,
                           perf_counts(counter->counts, cpu, thread)))
                return -1;
        }
    }

    return 0;
}

int perf_stat_process_counter(struct perf_stat_config *config,
                  struct perf_evsel *counter)
{
    struct perf_counts_values *aggr = &counter->counts->aggr;
    struct perf_stat_evsel *ps = counter->stats;
    u64 *count = counter->counts->aggr.values;
    int i, ret;

    aggr->val = aggr->ena = aggr->run = 0;

    /*
     * We calculate counter's data every interval,
     * and the display code shows ps->res_stats
     * avg value. We need to zero the stats for
     * interval mode, otherwise overall avg running
     * averages will be shown for each interval.
     */
    if (config->interval)
        init_stats(ps->res_stats);

    if (counter->per_pkg)
        zero_per_pkg(counter);

    ret = process_counter_maps(config, counter);
    if (ret)
        return ret;

    if (config->aggr_mode != AGGR_GLOBAL)
        return 0;

    if (!counter->snapshot)
        perf_evsel__compute_deltas(counter, -1, -1, aggr);
    perf_counts_values__scale(aggr, config->scale, &counter->counts->scaled);

    for (i = 0; i < 3; i++)
        update_stats(&ps->res_stats[i], count[i]);

    if (verbose > 0) {
        fprintf(config->output, "%s: %" PRIu64 " %" PRIu64 " %" PRIu64 "\n",
            perf_evsel__name(counter), count[0], count[1], count[2]);
    }

    /*
     * Save the full runtime - to allow normalization during printout:
     */
    perf_stat__update_shadow_stats(counter, *count, 0, &rt_stat);

    return 0;
}

int perf_event__process_stat_event(struct perf_tool *tool __maybe_unused,
                   union perf_event *event,
                   struct perf_session *session)
{
    struct perf_counts_values count;
    struct stat_event *st = &event->stat;
    struct perf_evsel *counter;

    count.val = st->val;
    count.ena = st->ena;
    count.run = st->run;

    counter = perf_evlist__id2evsel(session->evlist, st->id);
    if (!counter) {
        pr_err("Failed to resolve counter for stat event.\n");
        return -EINVAL;
    }

    *perf_counts(counter->counts, st->cpu, st->thread) = count;
    counter->supported = true;
    return 0;
}

size_t perf_event__fprintf_stat(union perf_event *event, FILE *fp)
{
    struct stat_event *st = (struct stat_event *) event;
    size_t ret;

    ret  = fprintf(fp, "\n... id %" PRIu64 ", cpu %d, thread %d\n",
               st->id, st->cpu, st->thread);
    ret += fprintf(fp, "... value %" PRIu64 ", enabled %" PRIu64 ", running %" PRIu64 "\n",
               st->val, st->ena, st->run);

    return ret;
}

size_t perf_event__fprintf_stat_round(union perf_event *event, FILE *fp)
{
    struct stat_round_event *rd = (struct stat_round_event *)event;
    size_t ret;

    ret = fprintf(fp, "\n... time %" PRIu64 ", type %s\n", rd->time,
              rd->type == PERF_STAT_ROUND_TYPE__FINAL ? "FINAL" : "INTERVAL");

    return ret;
}

size_t perf_event__fprintf_stat_config(union perf_event *event, FILE *fp)
{
    struct perf_stat_config sc;
    size_t ret;

    perf_event__read_stat_config(&sc, &event->stat_config);

    ret  = fprintf(fp, "\n");
    ret += fprintf(fp, "... aggr_mode %d\n", sc.aggr_mode);
    ret += fprintf(fp, "... scale     %d\n", sc.scale);
    ret += fprintf(fp, "... interval  %u\n", sc.interval);

    return ret;
}