/*
 *
 * syscall.c
 *
 * syscall: Benchmark for system call performance
 */
#include "../perf.h"
#include "../util/util.h"
#include <subcmd/parse-options.h>
#include "../builtin.h"
#include "bench.h"

#include <stdio.h>
#include <sys/time.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>

#ifndef __NR_fork
#define __NR_fork -1
#endif

static  int loops;

static const struct option options[] = {
        OPT_INTEGER('l', "loop",        &loops,         "Specify number of loops"),
        OPT_END()
};

static const char * const bench_syscall_usage[] = {
        "perf bench syscall <options>",
        NULL
};

static void test_fork(void)
{
        pid_t pid = fork();

        if (pid < 0) {
                fprintf(stderr, "fork failed\n");
                exit(1);
        } else if (pid == 0) {
                exit(0);
        } else {
                if (waitpid(pid, NULL, 0) < 0) {
                        fprintf(stderr, "waitpid failed\n");
                        exit(1);
                }
        }
}

static void test_execve(void)
{
        const char *pathname = "/bin/true";
        char *const argv[] = { (char *)pathname, NULL };
        pid_t pid = fork();

        if (pid < 0) {
                fprintf(stderr, "fork failed\n");
                exit(1);
        } else if (pid == 0) {
                execve(pathname, argv, NULL);
                fprintf(stderr, "execve /bin/true failed\n");
                exit(1);
        } else {
                if (waitpid(pid, NULL, 0) < 0) {
                        fprintf(stderr, "waitpid failed\n");
                        exit(1);
                }
        }
}

static int bench_syscall_common(int argc, const char **argv, int syscall)
{
        struct timeval start, stop, diff;
        unsigned long long result_usec = 0;
        const char *name = NULL;
        int i;

        switch (syscall) {
        case __NR_fork:
        case __NR_execve:
                /* Limit default loop to 10000 times to save time */
                loops = 10000;
                break;
        default:
                loops = 10000000;
                break;
        }

        /* Options -l and --loops override default above */
        argc = parse_options(argc, argv, options, bench_syscall_usage, 0);

        gettimeofday(&start, NULL);

        for (i = 0; i < loops; i++) {
                switch (syscall) {
                case __NR_getppid:
                        getppid();
                        break;
                case __NR_getpgid:
                        getpgid(0);
                        break;
                case __NR_fork:
                        test_fork();
                        break;
                case __NR_execve:
                        test_execve();
                default:
                        break;
                }
        }

        gettimeofday(&stop, NULL);
        timersub(&stop, &start, &diff);

        switch (syscall) {
        case __NR_getppid:
                name = "getppid()";
                break;
        case __NR_getpgid:
                name = "getpgid()";
                break;
        case __NR_fork:
                name = "fork()";
                break;
        case __NR_execve:
                name = "execve()";
                break;
        default:
                break;
        }

        switch (bench_format) {
        case BENCH_FORMAT_DEFAULT:
                printf("# Executed %'d %s calls\n", loops, name);

                result_usec = diff.tv_sec * 1000000;
                result_usec += diff.tv_usec;

                printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
                       (unsigned long) diff.tv_sec,
                       (unsigned long) (diff.tv_usec/1000));

                printf(" %14lf usecs/op\n",
                       (double)result_usec / (double)loops);
                printf(" %'14d ops/sec\n",
                       (int)((double)loops /
                             ((double)result_usec / (double)1000000)));
                break;

        case BENCH_FORMAT_SIMPLE:
                printf("%lu.%03lu\n",
                       (unsigned long) diff.tv_sec,
                       (unsigned long) (diff.tv_usec / 1000));
                break;

        default:
                /* reaching here is something disaster */
                fprintf(stderr, "Unknown format:%d\n", bench_format);
                exit(1);
                break;
        }

        return 0;
}

int bench_syscall_basic(int argc, const char **argv)
{
        return bench_syscall_common(argc, argv, __NR_getppid);
}

int bench_syscall_getpgid(int argc, const char **argv)
{
        return bench_syscall_common(argc, argv, __NR_getpgid);
}

int bench_syscall_fork(int argc, const char **argv)
{
        return bench_syscall_common(argc, argv, __NR_fork);
}

int bench_syscall_execve(int argc, const char **argv)
{
        return bench_syscall_common(argc, argv, __NR_execve);
}