/*

 * syst_smpl.c - example of a system-wide sampling

 *

 * 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.

 */

#include <sys/types.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <signal.h>

#include <getopt.h>

#include <setjmp.h>

#include <sys/ptrace.h>

#include <sys/wait.h>

#include <sys/poll.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <fcntl.h>

#include <err.h>

#include <locale.h>

#include "perf_util.h"

#define SMPL_PERIOD	240000000ULL

#define MAX_PATH	1024

#ifndef STR

# define _STR(x) #x

# define STR(x) _STR(x)

#endif

typedef struct {

	int opt_no_show;

	int mmap_pages;

	int cpu;

	int pin;

	int delay;

	char *events;

	char *cgroup;

} options_t;

static jmp_buf jbuf;

static uint64_t collected_samples, lost_samples;

static perf_event_desc_t *fds;

static int num_fds;

static options_t options;

static size_t pgsz;

static size_t map_size;

static struct option the_options[]={

	{ "help", 0, 0,  1},

	{ "no-show", 0, &options.opt_no_show, 1},

	{ 0, 0, 0, 0}

};

static const char *gen_events = "cycles,instructions";

static void

process_smpl_buf(perf_event_desc_t *hw)

{

	struct perf_event_header ehdr;

	int ret;

	for(;;) {

		ret = perf_read_buffer(hw, &ehdr, sizeof(ehdr));

		if (ret)

			return; /* nothing to read */

		switch(ehdr.type) {

			case PERF_RECORD_SAMPLE:

				ret = perf_display_sample(fds, num_fds, hw - fds, &ehdr, stdout);

				if (ret)

					errx(1, "cannot parse sample");

				collected_samples++;

				break;

			case PERF_RECORD_EXIT:

				display_exit(hw, stdout);

				break;

			case PERF_RECORD_LOST:

				lost_samples += display_lost(hw, fds, num_fds, stdout);

				break;

			case PERF_RECORD_THROTTLE:

				display_freq(1, hw, stdout);

				break;

			case PERF_RECORD_UNTHROTTLE:

				display_freq(0, hw, stdout);

				break;

			default:

				printf("unknown sample type %d\n", ehdr.type);

				perf_skip_buffer(hw, ehdr.size - sizeof(ehdr));

		}

	}

}

int

setup_cpu(int cpu, int fd)

{

	int ret, flags;

	int i, pid;

	/*

	 * does allocate fds

	 */

	ret = perf_setup_list_events(options.events, &fds, &num_fds);

	if (ret || !num_fds)

		errx(1, "cannot setup event list");

	if (!fds[0].hw.sample_period)

		errx(1, "need to set sampling period or freq on first event, use :period= or :freq=");

	fds[0].fd = -1;

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

		fds[i].hw.disabled = !i; /* start immediately */

		if (options.cgroup) {

			flags = PERF_FLAG_PID_CGROUP;

			pid = fd;

		} else {

			flags = 0;

			pid = -1;

		}

		if (options.pin)

			fds[i].hw.pinned = 1;

		if (fds[i].hw.sample_period) {

			/*

			 * set notification threshold to be halfway through the buffer

			 */

			if (fds[i].hw.sample_period) {

				fds[i].hw.wakeup_watermark = (options.mmap_pages*pgsz) / 2;

				fds[i].hw.watermark = 1;

			}

			fds[i].hw.sample_type = PERF_SAMPLE_IP|PERF_SAMPLE_TID|PERF_SAMPLE_READ|PERF_SAMPLE_TIME|PERF_SAMPLE_PERIOD|PERF_SAMPLE_STREAM_ID|PERF_SAMPLE_CPU;

			/*

			 * if we have more than one event, then record event identifier to help with parsing

			 */

			if (num_fds > 1)

				fds[i].hw.sample_type |= PERF_SAMPLE_IDENTIFIER;

			printf("%s period=%"PRIu64" freq=%d\n", fds[i].name, fds[i].hw.sample_period, fds[i].hw.freq);

			fds[i].hw.read_format = PERF_FORMAT_SCALE;

			if (fds[i].hw.freq)

				fds[i].hw.sample_type |= PERF_SAMPLE_PERIOD;

		}

		fds[i].fd = perf_event_open(&fds[i].hw, pid, cpu, fds[0].fd, flags);

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

			if (fds[i].hw.precise_ip)

				err(1, "cannot attach event %s: precise mode may not be supported", fds[i].name);

			err(1, "cannot attach event %s", fds[i].name);

		}

	}

	/*

	 * kernel adds the header page to the size of the mmapped region

	 */

	fds[0].buf = mmap(NULL, map_size, PROT_READ|PROT_WRITE, MAP_SHARED, fds[0].fd, 0);

	if (fds[0].buf == MAP_FAILED)

		err(1, "cannot mmap buffer");

	/* does not include header page */

	fds[0].pgmsk = (options.mmap_pages*pgsz)-1;

	/*

	 * send samples for all events to first event's buffer

	 */

	for (i = 1; i < num_fds; i++) {

		if (!fds[i].hw.sample_period)

			continue;

		ret = ioctl(fds[i].fd, PERF_EVENT_IOC_SET_OUTPUT, fds[0].fd);

		if (ret)

			err(1, "cannot redirect sampling output");

	}

	/*

	 * collect event ids

	 */

	if (num_fds > 1 && fds[0].fd > -1) {

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

			/*

			 * read the event identifier using ioctl

			 * new method replaced the trick with PERF_FORMAT_GROUP + PERF_FORMAT_ID + read()

			 */

			ret = ioctl(fds[i].fd, PERF_EVENT_IOC_ID, &fds[i].id);

			if (ret == -1)

				err(1, "cannot read ID");

			printf("ID %"PRIu64"  %s\n", fds[i].id, fds[i].name);

		}

	}

	return 0;

}

static void

start_cpu(void)

{

	int ret;

	ret = ioctl(fds[0].fd, PERF_EVENT_IOC_ENABLE, 0);

	if (ret)

		err(1, "cannot start counter");

}

static int

cgroupfs_find_mountpoint(char *buf, size_t maxlen)

{

	FILE *fp;

	char mountpoint[MAX_PATH+1], tokens[MAX_PATH+1], type[MAX_PATH+1];

	char *token, *saved_ptr = NULL;

	int found = 0;

	fp = fopen("/proc/mounts", "r");

	if (!fp)

		return -1;

	/*

	 * in order to handle split hierarchy, we need to scan /proc/mounts

	 * and inspect every cgroupfs mount point to find one that has

	 * perf_event subsystem

	 */

	while (fscanf(fp, "%*s %"STR(MAX_PATH)"s %"STR(MAX_PATH)"s %"

				STR(MAX_PATH)"s %*d %*d\n",

				mountpoint, type, tokens) == 3) {

		if (!strcmp(type, "cgroup")) {

			token = strtok_r(tokens, ",", &saved_ptr);

			while (token != NULL) {

				if (!strcmp(token, "perf_event")) {

					found = 1;

					break;

				}

				token = strtok_r(NULL, ",", &saved_ptr);

			}

		}

		if (found)

			break;

	}

	fclose(fp);

	if (!found)

		return -1;

	if (strlen(mountpoint) < maxlen) {

		strcpy(buf, mountpoint);

		return 0;

	}

	return -1;

}

int

open_cgroup(char *name)

{

        char path[MAX_PATH+1];

        char mnt[MAX_PATH+1];

        int cfd;

        if (cgroupfs_find_mountpoint(mnt, MAX_PATH+1))

                errx(1, "cannot find cgroup fs mount point");

        snprintf(path, MAX_PATH, "%s/%s", mnt, name);

        cfd = open(path, O_RDONLY);

        if (cfd == -1)

                warn("no access to cgroup %s\n", name);

        return cfd;

}

static void handler(int n)

{

	longjmp(jbuf, 1);

}

int

mainloop(char **arg)

{

	static uint64_t ovfl_count = 0; /* static to avoid setjmp issue */

	struct pollfd pollfds[1];

	int ret;

	int fd = -1;

	int i;

	if (pfm_initialize() != PFM_SUCCESS)

		errx(1, "libpfm initialization failed\n");

	pgsz = sysconf(_SC_PAGESIZE);

	map_size = (options.mmap_pages+1)*pgsz;

	if (options.cgroup) {

		fd = open_cgroup(options.cgroup);

		if (fd == -1)

			err(1, "cannot open cgroup file %s\n", options.cgroup);

	}

	setup_cpu(options.cpu, fd);

	/* done with cgroup */

	if (fd != -1)

		close(fd);

	signal(SIGALRM, handler);

	signal(SIGINT, handler);

	pollfds[0].fd = fds[0].fd;

	pollfds[0].events = POLLIN;

	printf("monitoring on CPU%d, session ending in %ds\n", options.cpu, options.delay);

	if (setjmp(jbuf) == 1)

		goto terminate_session;

	start_cpu();

	alarm(options.delay);

	/*

	 * core loop

	 */

	for(;;) {

		ret = poll(pollfds, 1, -1);

		if (ret < 0 && errno == EINTR)

			break;

		ovfl_count++;

		process_smpl_buf(&fds[0]);

	}

terminate_session:

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

		close(fds[i].fd);

	/* check for partial event buffer */

	process_smpl_buf(&fds[0]);

	munmap(fds[0].buf, map_size);

	perf_free_fds(fds, num_fds);

	printf("%"PRIu64" samples collected in %"PRIu64" poll events, %"PRIu64" lost samples\n",

		collected_samples,

		ovfl_count, lost_samples);

	return 0;

}

static void

usage(void)

{

	printf("usage: syst_smpl [-h] [-P] [--help] [-m mmap_pages] [-f] [-e event1,...,eventn] [-c cpu] [-d seconds]\n");

}

int

main(int argc, char **argv)

{

	int c;

	setlocale(LC_ALL, "");

	options.cpu = -1;

	options.delay = -1;

	while ((c=getopt_long(argc, argv,"hPe:m:c:d:G:", the_options, 0)) != -1) {

		switch(c) {

			case 0: continue;

			case 'e':

				if (options.events)

					errx(1, "events specified twice\n");

				options.events = optarg;

				break;

			case 'm':

				if (options.mmap_pages)

					errx(1, "mmap pages already set\n");

				options.mmap_pages = atoi(optarg);

				break;

			case 'P':

				options.pin = 1;

				break;

			case 'd':

				options.delay = atoi(optarg);

				break;

			case 'G':

				options.cgroup = optarg;

				break;

			case 'c':

				options.cpu = atoi(optarg);

				break;

			case 'h':

				usage();

				exit(0);

			default:

				errx(1, "unknown option");

		}

	}

	if (!options.events)

		options.events = strdup(gen_events);

	if (!options.mmap_pages)

		options.mmap_pages = 1;

	if (options.cpu == -1)

		options.cpu = random() % sysconf(_SC_NPROCESSORS_ONLN);

	if (options.delay == -1)

		options.delay = 10;

	if (options.mmap_pages > 1 && ((options.mmap_pages) & 0x1))

		errx(1, "number of pages must be power of 2\n");

	return mainloop(argv+optind);

}