#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->priv;

        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/),
};
#undef ID

void perf_stat_evsel_id_init(struct perf_evsel *evsel)
{
        struct perf_stat_evsel *ps = evsel->priv;
        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->priv;

        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->priv = zalloc(sizeof(struct perf_stat_evsel));
        if (evsel->priv == NULL)
                return -ENOMEM;
        perf_evsel__reset_stat_priv(evsel);
        return 0;
}

static void perf_evsel__free_stat_priv(struct perf_evsel *evsel)
{
        zfree(&evsel->priv);
}

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(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(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(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->values, cpu);
                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->priv;
        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) {
                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);

        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;
}