/*

 * notify_self3.c - example of how you can use overflow notifications with no messages

 *

 * Copyright (c) 2002-2006 Hewlett-Packard Development Company, L.P.

 * Contributed by Stephane Eranian <eranian@hpl.hp.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 <stdarg.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include <fcntl.h>

#include <perfmon/perfmon.h>

#include <perfmon/pfmlib.h>

#include "detect_pmcs.h"

#define SMPL_PERIOD	1000000000ULL

static volatile unsigned long notification_received;

#define NUM_PMCS PFMLIB_MAX_PMCS

#define NUM_PMDS PFMLIB_MAX_PMDS

static pfarg_pmr_t pdx[1];

static int ctx_fd;

static char *event1_name;

static void fatal_error(char *fmt,...) __attribute__((noreturn));

static void

fatal_error(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

	exit(1);

}

static void

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

{

	if (pfm_read(ctx_fd, 0, PFM_RW_PMD, pdx, sizeof(pdx)))

		fatal_error("pfm_read: %s", strerror(errno));

	/*

	 * we do not need to extract the overflow message, we know

	 * where it is coming from.

	 */

	/*

	 * increment our notification counter

	 */

	notification_received++;

	/*

	 * XXX: risky to do printf() in signal handler!

	 */

	if (event1_name)

		printf("Notification %02lu: %"PRIu64" %s\n", notification_received, pdx[0].reg_value, event1_name);

	else

		printf("Notification %02lu:\n", notification_received);

	/*

	 * And resume monitoring

	 */

	if (pfm_set_state(ctx_fd, 0, PFM_ST_RESTART))

		fatal_error("error pfm_set_state(restart): %d\n", errno);

}

/*

 * infinite loop waiting for notification to get out

 */

void

busyloop(void)

{

	/*

	 * busy loop to burn CPU cycles

	 */

	for(;notification_received < 40;) ;

}

#define BPL (sizeof(uint64_t)<<3)

#define LBPL	6

static inline void pfm_bv_set(uint64_t *bv, uint16_t rnum)

{

	bv[rnum>>LBPL] |= 1UL << (rnum&(BPL-1));

}

int

main(int argc, char **argv)

{

	int ret;

	pfmlib_input_param_t inp;

	pfmlib_output_param_t outp;

	pfarg_pmr_t pc[NUM_PMCS];

	pfarg_pmd_attr_t pd[NUM_PMDS];

	pfarg_sinfo_t sif;

	pfmlib_options_t pfmlib_options;

	struct sigaction act;

	size_t len;

	unsigned int i, num_counters;

	/*

	 * pass options to library (optional)

	 */

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

	pfmlib_options.pfm_debug = 0; /* set to 1 for debug */

	pfmlib_options.pfm_verbose = 1; /* set to 1 for verbose */

	pfm_set_options(&pfmlib_options);

	/*

	 * Initialize pfm library (required before we can use it)

	 */

	ret = pfm_initialize();

	if (ret != PFMLIB_SUCCESS)

		fatal_error("Cannot initialize library: %s\n", pfm_strerror(ret));

	/*

	 * Install the signal handler (SIGIO)

	 */

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

	act.sa_handler = (sig_t)sigio_handler;

	sigaction (SIGIO, &act, 0);

	memset(pc, 0, sizeof(pc));

	memset(pd, 0, sizeof(pd));

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

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

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

	pfm_get_num_counters(&num_counters);

	if (pfm_get_cycle_event(&inp.pfp_events[0]) != PFMLIB_SUCCESS)

		fatal_error("cannot find cycle event\n");

	if (pfm_get_inst_retired_event(&inp.pfp_events[1]) != PFMLIB_SUCCESS)

		fatal_error("cannot find inst retired event\n");

	i = 2;

	/*

	 * set the default privilege mode for all counters:

	 * 	PFM_PLM3 : user level only

	 */

	inp.pfp_dfl_plm = PFM_PLM3;

	if (i > num_counters) {

		i = num_counters;

		printf("too many events provided (max=%d events), using first %d event(s)\n", num_counters, i);

	}

	/*

	 * how many counters we use

	 */

	inp.pfp_event_count = i;

	if (i > 1) {

		pfm_get_max_event_name_len(&len;;

		event1_name = malloc(len+1);

		if (event1_name == NULL)

			fatal_error("cannot allocate event name\n");

		pfm_get_full_event_name(&inp.pfp_events[1], event1_name, len+1);

	}

	/*

	 * when we know we are self-monitoring and we have only one session, then

	 * when we get an overflow we know where it is coming from. Therefore we can

	 * save the call to the kernel to extract the notification message. By default,

	 * a message is generated. The queue of messages has a limited size, therefore

	 * it is important to clear the queue by reading the message on overflow. Failure

	 * to do so may result in a queue full and you will lose notification messages.

	 *

	 * With the PFM_FL_OVFL_NO_MSG, no message will be queue, but you will still get

	 * the signal. Similarly, the PFM_MSG_END will be generated.

	 */

	ctx_fd = pfm_create(PFM_FL_OVFL_NO_MSG, &sif;;

	if (ctx_fd == -1) {

		if (errno == ENOSYS) {

			fatal_error("Your kernel does not have performance monitoring support!\n");

		}

		fatal_error("cannot create session %s\n", strerror(errno));

	}

	/*

	 * build the pfp_unavail_pmcs bitmask by looking

	 * at what perfmon has available. It is not always

	 * the case that all PMU registers are actually available

	 * to applications. For instance, on IA-32 platforms, some

	 * registers may be reserved for the NMI watchdog timer.

	 *

	 * With this bitmap, the library knows which registers NOT to

	 * use. Of source, it is possible that no valid assignement may

	 * be possible if certina PMU registers  are not available.

	 */

	detect_unavail_pmu_regs(&sif, &inp.pfp_unavail_pmcs, NULL);

	/*

	 * let the library figure out the values for the PMCS

	 */

	if ((ret=pfm_dispatch_events(&inp, NULL, &outp, NULL)) != PFMLIB_SUCCESS)

		fatal_error("Cannot configure events: %s\n", pfm_strerror(ret));

	/*

	 * Now prepare the argument to initialize the PMDs and PMCS.

	 */

	for (i=0; i < outp.pfp_pmc_count; i++) {

		pc[i].reg_num   = outp.pfp_pmcs[i].reg_num;

		pc[i].reg_value = outp.pfp_pmcs[i].reg_value;

	}

	for (i=0; i < outp.pfp_pmd_count; i++)

		pd[i].reg_num = outp.pfp_pmds[i].reg_num;

	/*

	 * We want to get notified when the counter used for our first

	 * event overflows

	 */

	pd[0].reg_flags	|= PFM_REGFL_OVFL_NOTIFY;

	if (inp.pfp_event_count > 1) {

		pfm_bv_set(pd[0].reg_reset_pmds, pd[1].reg_num);

		pdx[0].reg_num = pd[1].reg_num;

	}

	/*

	 * we arm the first counter, such that it will overflow

	 * after SMPL_PERIOD events have been observed

	 */

	pd[0].reg_value       = - SMPL_PERIOD;

	pd[0].reg_long_reset  = - SMPL_PERIOD;

	pd[0].reg_short_reset = - SMPL_PERIOD;

	/*

	 * Now program the registers

	 */

	if (pfm_write(ctx_fd, 0, PFM_RW_PMC, pc, outp.pfp_pmc_count * sizeof(*pc)))

		fatal_error("pfm_write error errno %d\n",errno);

	if (pfm_write(ctx_fd, 0, PFM_RW_PMD_ATTR, pd, outp.pfp_pmd_count * sizeof(*pd)))

		fatal_error("pfm_write(PMD) error errno %d\n",errno);

	/*

	 * we want to monitor ourself

	 */

	if (pfm_attach(ctx_fd, 0, getpid()))

		fatal_error("pfm_attach error errno %d\n",errno);

	/*

	 * setup asynchronous notification on the file descriptor

	 */

	ret = fcntl(ctx_fd, F_SETFL, fcntl(ctx_fd, F_GETFL, 0) | O_ASYNC);

	if (ret == -1)

		fatal_error("cannot set ASYNC: %s\n", strerror(errno));

	/*

	 * get ownership of the descriptor

	 */

	ret = fcntl(ctx_fd, F_SETOWN, getpid());

	if (ret == -1)

		fatal_error("cannot setown: %s\n", strerror(errno));

	/*

	 * Let's roll now

	 */

	if (pfm_set_state(ctx_fd, 0, PFM_ST_START))

		fatal_error("pfm_set_state(start) error errno %d\n", errno);

	busyloop();

	if (pfm_set_state(ctx_fd, 0, PFM_ST_STOP))

		fatal_error("pfm_set_state(stop) error errno %d\n", errno);

	/*

	 * destroy our session

	 */

	close(ctx_fd);

	if (event1_name)

		free(event1_name);

	return 0;

}