source: mainline/uspace/app/rcubench/rcubench.c@ b188002

/*
 * Copyright (c) 2012 Adam Hraska
 * 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 test
 * @{
 */

/**
 * @file rcubench.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <mem.h>
#include <errno.h>
#include <thread.h>
#include <assert.h>
#include <async.h>
#include <fibril.h>
#include <fibril_synch.h>
#include <compiler/barrier.h>
#include <futex.h>

#include <rcu.h>

typedef struct bench {
        enum {
                T_KERN_FUTEX,
                T_LIBC_FUTEX
        } type;
        size_t iters;
        size_t nthreads;
        size_t array_size;
        size_t *array;
        futex_t done_threads;
        
        futex_t ke_bench_fut;
        fibril_mutex_t libc_bench_mtx;
} bench_t;


/* Combats compiler optimizations. */
static volatile size_t dummy = 0;

static size_t sum_array(size_t *array, size_t len)
{
        size_t sum = 0;
        
        for (size_t k = 0; k < len; ++k)
                sum += array[k];
        
        return sum;
}


static void  kernel_futex_bench(bench_t *bench)
{
        futex_t * const fut = &bench->ke_bench_fut;
        const size_t iters = bench->iters;
        size_t sum = 0;
        
        for (size_t i = 0; i < iters; ++i) {
                /* Do some work with the futex locked to encourage contention. */
                futex_down(fut);
                sum += sum_array(bench->array, bench->array_size);
                futex_up(fut);
                
                /* 
                 * Do half as much work to give other threads a chance to acquire 
                 * the futex.
                 */
                sum += sum_array(bench->array, bench->array_size / 2);
        }
        
        /* 
         * Writing to a global volatile variable separated with a cc-barrier
         * should discourage the compiler from optimizing away sum_array()s.
         */
        compiler_barrier();
        dummy = sum;
}

static void libc_futex_bench(bench_t *bench)
{
        fibril_mutex_t * const mtx = &bench->libc_bench_mtx;
        const size_t iters = bench->iters;
        
        for (size_t i = 0; i < iters; ++i) {
                fibril_mutex_lock(mtx);
                /* no-op */
                compiler_barrier();
                fibril_mutex_unlock(mtx);
        }
}


static void thread_func(void *arg)
{
        bench_t *bench = (bench_t*)arg;
        
        switch (bench->type) {
        case T_KERN_FUTEX:
                kernel_futex_bench(bench);
                break;
        case T_LIBC_FUTEX:
                libc_futex_bench(bench);
                break;
        default:
                assert(false);
        }
        
        /* Signal another thread completed. */
        futex_up(&bench->done_threads);
}

static void run_threads_and_wait(bench_t *bench)
{
        assert(1 <= bench->nthreads);
        
        if (2 <= bench->nthreads) {
                printf("Creating %zu additional threads...\n", bench->nthreads - 1);
        }
        
        /* Create and run the first nthreads - 1 threads.*/
        for (size_t k = 1; k < bench->nthreads; ++k) {
                thread_id_t tid;
                /* Also sets up a fibril for the thread. */
                int ret = thread_create(thread_func, bench, "rcubench-t", &tid);
                if (ret != EOK) {
                        printf("Error: Failed to create benchmark thread.\n");
                        abort();
                }
                thread_detach(tid);
        }
        
        /* 
         * Run the last thread in place so that we create multiple threads
         * only when needed. Otherwise libc would immediately upgrade
         * single-threaded futexes to proper multithreaded futexes
         */
        thread_func(bench);
        
        printf("Waiting for remaining threads to complete.\n");
        
        /* Wait for threads to complete. */
        for (size_t k = 0; k < bench->nthreads; ++k) {
                futex_down(&bench->done_threads);
        }
}

static void print_usage(void)
{
        printf("rcubench [test-name] [k-iterations] [n-threads] {work-size}\n");
        printf("eg:\n");
        printf("  rcubench ke   100000 3 4\n");
        printf("  rcubench libc 100000 2\n");
        printf("  rcubench def-ke  \n");
        printf("  rcubench def-libc\n");
}

static bool parse_cmd_line(int argc, char **argv, bench_t *bench, 
        const char **err)
{
        if (argc < 2) {
                *err = "Benchmark name not specified";
                return false;
        }

        futex_initialize(&bench->ke_bench_fut, 1);
        fibril_mutex_initialize(&bench->libc_bench_mtx);
        
        if (0 == str_cmp(argv[1], "def-ke")) {
                bench->type = T_KERN_FUTEX;
                bench->nthreads = 4;
                bench->iters = 1000 * 1000;
                bench->array_size = 10;
                bench->array = malloc(bench->array_size * sizeof(size_t));
                return NULL != bench->array;
        } else if (0 == str_cmp(argv[1], "def-libc")) {
                bench->type = T_LIBC_FUTEX;
                bench->nthreads = 4;
                bench->iters = 1000 * 1000;
                bench->array_size = 0;
                bench->array = NULL;
                return true;
        } else if (0 == str_cmp(argv[1], "ke")) {
                bench->type = T_KERN_FUTEX;
        } else if (0 == str_cmp(argv[1], "libc")) {
                bench->type = T_LIBC_FUTEX;
        } else {
                *err = "Unknown test name";
                return false;
        }
        
        if (argc < 4) {
                *err = "Not enough parameters";
                return false;
        }
        
        uint32_t iter_cnt = 0;
        int ret = str_uint32_t(argv[2], NULL, 0, true, &iter_cnt);

        if (ret == EOK && 1 <= iter_cnt) {
                bench->iters = iter_cnt;
        } else {
                *err = "Err: Invalid number of iterations";
                return false;
        } 
        
        uint32_t thread_cnt = 0;
        ret = str_uint32_t(argv[3], NULL, 0, true, &thread_cnt);

        if (ret == EOK && 1 <= thread_cnt && thread_cnt <= 64) {
                bench->nthreads = thread_cnt;
        } else {
                *err = "Err: Invalid number of threads";
                return false;
        } 
        
        if (argc > 4) {
                uint32_t work_size = 0;
                ret = str_uint32_t(argv[4], NULL, 0, true, &work_size);

                if (ret == EOK && work_size <= 10000) {
                        bench->array_size = work_size;
                } else {
                        *err = "Err: Work size too large";
                        return false;
                } 
        } else {
                bench->array_size = 0;
        }
        
        if (0 < bench->array_size) {
                bench->array = malloc(bench->array_size * sizeof(size_t));
                if (!bench->array) {
                        *err = "Err: Failed to allocate work array";
                        return false;
                }
        } else {
                bench->array = NULL;
        }
        
        return true;
}

int main(int argc, char **argv)
{
        const char *err = "(error)";
        bench_t bench;
        
        futex_initialize(&bench.done_threads, 0);
        
        if (!parse_cmd_line(argc, argv, &bench, &err)) {
                printf("%s\n", err);
                print_usage();
                return -1;
        }
        
        printf("Running '%s' futex bench in '%zu' threads with '%zu' iterations.\n",
                bench.type == T_KERN_FUTEX ? "kernel" : "libc", 
                bench.nthreads, bench.iters);
        
        struct timeval start, end;
        getuptime(&start);
        
        run_threads_and_wait(&bench);
        
        getuptime(&end);
        int64_t duration = tv_sub(&end, &start);
        
        if (0 == duration)
                duration = 1;
        
        uint64_t secs = (uint64_t)duration / 1000 / 1000;
        uint64_t total_iters = (uint64_t)bench.iters * bench.nthreads;
        uint64_t iters_per_sec = total_iters * 1000 * 1000 / duration;
        
        printf("Completed %" PRIu64 " iterations in %" PRId64  " usecs (%" PRIu64 
                " secs); %" PRIu64 " iters/sec\n", 
                total_iters, duration, secs, iters_per_sec);    
        
        return 0;
}


/**
 * @}
 */