/*

 * notify_group.c - self-sampling multuiple events in one group

 *

 * Copyright (c) 2009 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.

 */

#include <sys/types.h>

#include <inttypes.h>

#include <stdio.h>

#include <stdlib.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include <fcntl.h>

#include <err.h>

#include <sys/prctl.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include "perf_util.h"

#define SMPL_PERIOD	2400000000ULL

typedef struct {

	uint64_t	ip;

} sample_t;

static volatile unsigned long notification_received;

static perf_event_desc_t *fds;

static int num_fds;

static int buffer_pages = 1; /* size of buffer payload  (must be power of 2) */

static void

sigio_handler(int n, siginfo_t *info, struct sigcontext *sc)

{

	struct perf_event_header ehdr;

	uint64_t ip;

	int id, ret;

	id = perf_fd2event(fds, num_fds, info->si_fd);

	if (id == -1)

		errx(1, "cannot find event for descriptor %d", info->si_fd);

	ret = perf_read_buffer(fds+id, &ehdr, sizeof(ehdr));

	if (ret)

		errx(1, "cannot read event header");

	if (ehdr.type != PERF_RECORD_SAMPLE) {

		warnx("unknown event type %d, skipping", ehdr.type);

		perf_skip_buffer(fds+id, ehdr.size - sizeof(ehdr));

		goto skip;

	}

	ret = perf_read_buffer(fds+id, &ip, sizeof(ip));

	if (ret)

		errx(1, "cannot read IP");

	notification_received++;

	printf("Notification %lu: 0x%"PRIx64" fd=%d %s\n",

		notification_received,

		ip,

		info->si_fd, fds[id].name);

skip:

	/*

 	 * rearm the counter for one more shot

 	 */

	ret = ioctl(info->si_fd, PERF_EVENT_IOC_REFRESH, 1);

	if (ret == -1)

		err(1, "cannot refresh");

}

/*

 * infinite loop waiting for notification to get out

 */

void

busyloop(void)

{

	/*

	 * busy loop to burn CPU cycles

	 */

	for(;notification_received < 1024;) ;

}

int

main(int argc, char **argv)

{

	struct sigaction act;

	sigset_t new, old;

	size_t pgsz;

	int ret, i;

	ret = pfm_initialize();

	if (ret != PFM_SUCCESS)

		errx(1, "Cannot initialize library: %s", pfm_strerror(ret));

	pgsz = sysconf(_SC_PAGESIZE);

	/*

	 * Install the signal handler (SIGIO)

	 */

	memset(&act, 0, sizeof(act));

	act.sa_sigaction = (void *)sigio_handler;

	act.sa_flags = SA_SIGINFO;

	sigaction (SIGIO, &act, 0);

	sigemptyset(&old;;

	sigemptyset(&new;;

	sigaddset(&new, SIGIO);

	ret = sigprocmask(SIG_SETMASK, NULL, &old;;

	if (ret)

		err(1, "sigprocmask failed");

	if (sigismember(&old, SIGIO)) {

		warnx("program started with SIGIO masked, unmasking it now\n");

		ret = sigprocmask(SIG_UNBLOCK, &new, NULL);

		if (ret)

			err(1, "sigprocmask failed");

	}

	/*

 	 * allocates fd for us

 	 */

	ret = perf_setup_list_events("cycles,"

				       "instructions,"

					"cycles",

				        &fds, &num_fds);

	if (ret || !num_fds)

		exit(1);

	fds[0].fd = -1;

	for(i=0; i < num_fds; i++) {

		/* want a notification for each sample added to the buffer */

		fds[i].hw.disabled =  !!i;

		printf("i=%d disabled=%d\n", i, fds[i].hw.disabled);

		fds[i].hw.wakeup_events = 1;

		fds[i].hw.sample_type = PERF_SAMPLE_IP;

		fds[i].hw.sample_period = SMPL_PERIOD;

		fds[i].fd = perf_event_open(&fds[i].hw, 0, -1, fds[0].fd, 0);

		if (fds[i].fd == -1) {

			warn("cannot attach event %s", fds[i].name);

			goto error;

		}

		fds[i].buf = mmap(NULL, (buffer_pages + 1)*pgsz, PROT_READ|PROT_WRITE, MAP_SHARED, fds[i].fd, 0);

		if (fds[i].buf == MAP_FAILED)

			err(1, "cannot mmap buffer");

		/*

		 * setup asynchronous notification on the file descriptor

		 */

		ret = fcntl(fds[i].fd, F_SETFL, fcntl(fds[i].fd, F_GETFL, 0) | O_ASYNC);

		if (ret == -1)

			err(1, "cannot set ASYNC");

		/*

		 * necessary if we want to get the file descriptor for

		 * which the SIGIO is sent for in siginfo->si_fd.

		 * SA_SIGINFO in itself is not enough

		 */

		ret = fcntl(fds[i].fd, F_SETSIG, SIGIO);

		if (ret == -1)

			err(1, "cannot setsig");

		/*

		 * get ownership of the descriptor

		 */

		ret = fcntl(fds[i].fd, F_SETOWN, getpid());

		if (ret == -1)

			err(1, "cannot setown");

		fds[i].pgmsk = (buffer_pages * pgsz) - 1;

	}

	for(i=0; i < num_fds; i++) {

		ret = ioctl(fds[i].fd, PERF_EVENT_IOC_REFRESH , 1);

		if (ret == -1)

			err(1, "cannot refresh");

	}

	busyloop();

	prctl(PR_TASK_PERF_EVENTS_DISABLE);

error:

	/*

	 * destroy our session

	 */

	for(i=0; i < num_fds; i++)

		if (fds[i].fd > -1)

			close(fds[i].fd);

	perf_free_fds(fds, num_fds);

	/* free libpfm resources cleanly */

	pfm_terminate();

	return 0;

}