op_perf_events_checker.c

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/*
 * @file op-perf-events-checker.c
 *
 * Utility program for determining the existence and functionality
 * of the Linux kernel's Performance Events Subsystem.
 *
 * @remark Copyright 2011 OProfile authors
 * @remark Read the file COPYING
 *
 * Created on: Dec 7, 2011
 * @author Maynard Johnson
 * (C) Copyright IBM Corp. 2011
 *
 */

#include <sys/types.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include "config.h"
#if HAVE_PERF_EVENTS
#include <linux/perf_event.h>
    struct perf_event_attr attr;
    pid_t pid ;
#endif

static void usage(void)
{
    fprintf(stderr, "usage: op-check-perfevents [OPTION]\n");
    fprintf(stderr, "\t-h, --help\t\tPrint this help message\n");
    fprintf(stderr, "\t-v, --verbose\t\tPrint errno value of perf_event_open syscall\n");
}

int main(int argc, char **argv)
{
    int _verbose = 0;
    if (argc > 1) {
        if ((!strcmp(argv[1], "-h")) || (!strcmp(argv[1], "--help"))) {
            usage();
            return 0;
        } else if ((!strcmp(argv[1], "-v")) || (!strcmp(argv[1], "--verbose"))) {
            _verbose = 1;
        } else {
            usage();
            return -1;
        }
    }

#if HAVE_PERF_EVENTS
    /* If perf_events syscall is not implemented, the syscall below will fail
     * with ENOSYS (38).  If implemented, but the processor type on which this
     * program is running is not supported by perf_events, the syscall returns
     * ENOENT (2).
     */
        memset(&attr, 0, sizeof(attr));
        attr.size = sizeof(attr);
        attr.sample_type = PERF_SAMPLE_IP;

    pid = getpid();
    syscall(__NR_perf_event_open, &attr, pid, 0, -1, 0);
    if (_verbose)
        fprintf(stderr, "perf_event_open syscall returned %s\n", strerror(errno));
    return errno;
#else
    return -1;
#endif
}