/*
* self-basic.c - example of a simple self monitoring task no-helper
*
* Copyright (c) 2010 Google, Inc
* Contributed by Stephane Eranian <eranian@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* This file is part of libpfm, a performance monitoring support library for
* applications on Linux.
*/
#include <sys/types.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <locale.h>
#include <sys/ioctl.h>
#include <err.h>
#include <perfmon/pfmlib_perf_event.h>
#define N 30
static unsigned long
fib(unsigned long n)
{
if (n == 0)
return 0;
if (n == 1)
return 2;
return fib(n-1)+fib(n-2);
}
int
main(int argc, char **argv)
{
struct perf_event_attr attr;
int fd, ret;
uint64_t count = 0, values[3];
setlocale(LC_ALL, "");
/*
* Initialize libpfm library (required before we can use it)
*/
ret = pfm_initialize();
if (ret != PFM_SUCCESS)
errx(1, "cannot initialize library: %s", pfm_strerror(ret));
memset(&attr, 0, sizeof(attr));
/*
* 1st argument: event string
* 2nd argument: default privilege level (used if not specified in the event string)
* 3rd argument: the perf_event_attr to initialize
*/
ret = pfm_get_perf_event_encoding("cycles", PFM_PLM0|PFM_PLM3, &attr, NULL, NULL);
if (ret != PFM_SUCCESS)
errx(1, "cannot find encoding: %s", pfm_strerror(ret));
/*
* request timing information because event may be multiplexed
* and thus it may not count all the time. The scaling information
* will be used to scale the raw count as if the event had run all
* along
*/
attr.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING;
/* do not start immediately after perf_event_open() */
attr.disabled = 1;
/*
* create the event and attach to self
* Note that it attaches only to the main thread, there is no inheritance
* to threads that may be created subsequently.
*
* if mulithreaded, then getpid() must be replaced by gettid()
*/
fd = perf_event_open(&attr, getpid(), -1, -1, 0);
if (fd < 0)
err(1, "cannot create event");
/*
* start counting now
*/
ret = ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);
if (ret)
err(1, "ioctl(enable) failed");
printf("Fibonacci(%d)=%lu\n", N, fib(N));
/*
* stop counting
*/
ret = ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
if (ret)
err(1, "ioctl(disable) failed");
/*
* read the count + scaling values
*
* It is not necessary to stop an event to read its value
*/
ret = read(fd, values, sizeof(values));
if (ret != sizeof(values))
err(1, "cannot read results: %s", strerror(errno));
/*
* scale count
*
* values[0] = raw count
* values[1] = TIME_ENABLED
* values[2] = TIME_RUNNING
*/
if (values[2])
count = (uint64_t)((double)values[0] * values[1]/values[2]);
printf("count=%'"PRIu64"\n", count);
close(fd);
/* free libpfm resources cleanly */
pfm_terminate();
return 0;
}