source: mainline/uspace/app/perf/perf.c@ b4a4ad94

/*
 * Copyright (c) 2018 Jiri Svoboda
 * Copyright (c) 2018 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup perf
 * @{
 */
/**
 * @file
 */

#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <str.h>
#include <time.h>
#include <errno.h>
#include <perf.h>
#include <types/casting.h>
#include "perf.h"
#include "benchlist.h"

#define MIN_DURATION_SECS 10
#define NUM_SAMPLES 10
#define MAX_ERROR_STR_LENGTH 1024

static void short_report(stopwatch_t *stopwatch, int run_index,
    benchmark_t *bench, uint64_t workload_size)
{
        usec_t duration_usec = NSEC2USEC(stopwatch_get_nanos(stopwatch));

        printf("Completed %" PRIu64 " operations in %llu us",
            workload_size, duration_usec);
        if (duration_usec > 0) {
                double nanos = stopwatch_get_nanos(stopwatch);
                double thruput = (double) workload_size / (nanos / 1000000000.0l);
                printf(", %.0f ops/s.\n", thruput);
        } else {
                printf(".\n");
        }
}

/*
 * This is a temporary solution until we have proper sqrt() implementation
 * in libmath.
 *
 * The algorithm uses Babylonian method [1].
 *
 * [1] https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method
 */
static double estimate_square_root(double value, double precision)
{
        double estimate = 1.;
        double prev_estimate = estimate + 10 * precision;

        while (fabs(estimate - prev_estimate) > precision) {
                prev_estimate = estimate;
                estimate = (prev_estimate + value / prev_estimate) / 2.;
        }

        return estimate;
}

/*
 * Compute available statistics from given stopwatches.
 *
 * We compute normal mean for average duration of the workload and geometric
 * mean for average thruput. Note that geometric mean is necessary to compute
 * average throughput correctly - consider the following example:
 *  - we run always 60 operations,
 *  - first run executes in 30 s (i.e. 2 ops/s)
 *  - and second one in 10 s (6 ops/s).
 * Then, naively, average throughput would be (2+6)/2 = 4 [ops/s]. However, we
 * actually executed 60 + 60 ops in 30 + 10 seconds. So the actual average
 * throughput is 3 ops/s (which is exactly what geometric mean means).
 *
 */
static void compute_stats(stopwatch_t *stopwatch, size_t stopwatch_count,
    uint64_t workload_size, double precision, double *out_duration_avg,
    double *out_duration_sigma, double *out_thruput_avg)
{
        double inv_thruput_sum = 0.0;
        double nanos_sum = 0.0;
        double nanos_sum2 = 0.0;

        for (size_t i = 0; i < stopwatch_count; i++) {
                double nanos = stopwatch_get_nanos(&stopwatch[i]);
                double thruput = (double) workload_size / nanos;

                inv_thruput_sum += 1.0 / thruput;
                nanos_sum += nanos;
                nanos_sum2 += nanos * nanos;
        }
        *out_duration_avg = nanos_sum / stopwatch_count;
        double sigma2 = (nanos_sum2 - nanos_sum * (*out_duration_avg)) /
            ((double) stopwatch_count - 1);
        // FIXME: implement sqrt properly
        *out_duration_sigma = estimate_square_root(sigma2, precision);
        *out_thruput_avg = 1.0 / (inv_thruput_sum / stopwatch_count);
}

static void summary_stats(stopwatch_t *stopwatch, size_t stopwatch_count,
    benchmark_t *bench, uint64_t workload_size)
{
        double duration_avg, duration_sigma, thruput_avg;
        compute_stats(stopwatch, stopwatch_count, workload_size, 0.001,
            &duration_avg, &duration_sigma, &thruput_avg);

        printf("Average: %" PRIu64 " ops in %.0f us (sd %.0f us); "
            "%.0f ops/s; Samples: %zu\n",
            workload_size, duration_avg / 1000.0, duration_sigma / 1000.0,
            thruput_avg * 1000000000.0, stopwatch_count);
}

static bool run_benchmark(benchmark_t *bench)
{
        printf("Warm up and determine workload size...\n");

        char *error_msg = malloc(MAX_ERROR_STR_LENGTH + 1);
        if (error_msg == NULL) {
                printf("Out of memory!\n");
                return false;
        }
        str_cpy(error_msg, MAX_ERROR_STR_LENGTH, "");

        bool ret = true;

        if (bench->setup != NULL) {
                ret = bench->setup(error_msg, MAX_ERROR_STR_LENGTH);
                if (!ret) {
                        goto leave_error;
                }
        }

        /*
         * Find workload size that is big enough to last few seconds.
         * We also check that uint64_t is big enough.
         */
        uint64_t workload_size = 0;
        for (size_t bits = 0; bits <= 64; bits++) {
                if (bits == 64) {
                        str_cpy(error_msg, MAX_ERROR_STR_LENGTH, "Workload too small even for 1 << 63");
                        goto leave_error;
                }
                workload_size = ((uint64_t) 1) << bits;

                stopwatch_t stopwatch = STOPWATCH_INITIALIZE_STATIC;

                bool ok = bench->entry(&stopwatch, workload_size,
                    error_msg, MAX_ERROR_STR_LENGTH);
                if (!ok) {
                        goto leave_error;
                }
                short_report(&stopwatch, -1, bench, workload_size);

                nsec_t duration = stopwatch_get_nanos(&stopwatch);
                if (duration > SEC2NSEC(MIN_DURATION_SECS)) {
                        break;
                }
        }

        printf("Workload size set to %" PRIu64 ", measuring %d samples.\n", workload_size, NUM_SAMPLES);

        stopwatch_t *stopwatch = calloc(NUM_SAMPLES, sizeof(stopwatch_t));
        if (stopwatch == NULL) {
                snprintf(error_msg, MAX_ERROR_STR_LENGTH, "failed allocating memory");
                goto leave_error;
        }
        for (int i = 0; i < NUM_SAMPLES; i++) {
                stopwatch_init(&stopwatch[i]);

                bool ok = bench->entry(&stopwatch[i], workload_size,
                    error_msg, MAX_ERROR_STR_LENGTH);
                if (!ok) {
                        free(stopwatch);
                        goto leave_error;
                }
                short_report(&stopwatch[i], i, bench, workload_size);
        }

        summary_stats(stopwatch, NUM_SAMPLES, bench, workload_size);
        printf("\nBenchmark completed\n");

        free(stopwatch);

        goto leave;

leave_error:
        printf("Error: %s\n", error_msg);
        ret = false;

leave:
        if (bench->teardown != NULL) {
                bool ok = bench->teardown(error_msg, MAX_ERROR_STR_LENGTH);
                if (!ok) {
                        printf("Error: %s\n", error_msg);
                        ret = false;
                }
        }

        free(error_msg);

        return ret;
}

static int run_benchmarks(void)
{
        unsigned int count_ok = 0;
        unsigned int count_fail = 0;

        char *failed_names = NULL;

        printf("\n*** Running all benchmarks ***\n\n");

        for (size_t it = 0; it < benchmark_count; it++) {
                printf("%s (%s)\n", benchmarks[it]->name, benchmarks[it]->desc);
                if (run_benchmark(benchmarks[it])) {
                        count_ok++;
                        continue;
                }

                if (!failed_names) {
                        failed_names = str_dup(benchmarks[it]->name);
                } else {
                        char *f = NULL;
                        asprintf(&f, "%s, %s", failed_names, benchmarks[it]->name);
                        if (!f) {
                                printf("Out of memory.\n");
                                abort();
                        }
                        free(failed_names);
                        failed_names = f;
                }
                count_fail++;
        }

        printf("\nCompleted, %u benchmarks run, %u succeeded.\n",
            count_ok + count_fail, count_ok);
        if (failed_names)
                printf("Failed benchmarks: %s\n", failed_names);

        return count_fail;
}

static void list_benchmarks(void)
{
        size_t len = 0;
        for (size_t i = 0; i < benchmark_count; i++) {
                size_t len_now = str_length(benchmarks[i]->name);
                if (len_now > len)
                        len = len_now;
        }

        assert(can_cast_size_t_to_int(len) && "benchmark name length overflow");

        for (size_t i = 0; i < benchmark_count; i++)
                printf("%-*s %s\n", (int) len, benchmarks[i]->name, benchmarks[i]->desc);

        printf("%-*s Run all benchmarks\n", (int) len, "*");
}

int main(int argc, char *argv[])
{
        if (argc < 2) {
                printf("Usage:\n\n");
                printf("%s <benchmark>\n\n", argv[0]);
                list_benchmarks();
                return 0;
        }

        if (str_cmp(argv[1], "*") == 0) {
                return run_benchmarks();
        }

        for (size_t i = 0; i < benchmark_count; i++) {
                if (str_cmp(argv[1], benchmarks[i]->name) == 0) {
                        return (run_benchmark(benchmarks[i]) ? 0 : -1);
                }
        }

        printf("Unknown benchmark \"%s\"\n", argv[1]);
        return -2;
}

/** @}
 */