/*

 * smpl_pebs.c - PEBS standalone (no libpfm) sampling example for P4/Xeon

 * 		 (support 32-bit and 64-bit modes)

 *

 * Copyright (c) 2005-2006 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.

 *

 * This file is part of libpfm, a performance monitoring support library for

 * applications on Linux.

 */

#ifndef _GNU_SOURCE

  #define _GNU_SOURCE /* for getline */

#endif

#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 <syscall.h>

#include <unistd.h>

#include <sys/wait.h>

#include <sys/ptrace.h>

#include <sys/mman.h>

#include <perfmon/perfmon.h>

#include <perfmon/perfmon_pebs_p4_smpl.h>

#define NUM_PMCS	32

#define NUM_PMDS	32

#define SMPL_PERIOD	100000ULL	 /* must not use more bits than actual HW counter width */

typedef pfm_pebs_p4_smpl_hdr_t		smpl_hdr_t;

typedef pfm_pebs_p4_smpl_entry_t	smpl_entry_t;

typedef pfm_pebs_p4_smpl_arg_t		smpl_arg_t;

#define FMT_NAME			PFM_PEBS_P4_SMPL_NAME

static uint64_t collected_samples;

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

warning(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

}

int

child(char **arg)

{

	/*

	 * force the task to stop before executing the first

	 * user level instruction

	 */

	ptrace(PTRACE_TRACEME, 0, NULL, NULL);

	execvp(arg[0], arg);

	/* not reached */

	exit(1);

}

static void

process_smpl_buf(smpl_hdr_t *hdr)

{

	static uint64_t last_overflow = ~0; /* initialize to biggest value possible */

	static uint64_t last_count;

	smpl_entry_t *ent;

	unsigned long count;

	uint64_t entry;

	count = (hdr->ds.pebs_index - hdr->ds.pebs_buf_base)/sizeof(*ent);

	if (hdr->overflows == last_overflow && last_count == count) {

		warning("skipping identical set of samples %"PRIu64" = %"PRIu64"\n",

			hdr->overflows, last_overflow);

		return;	

	}

	last_count = count;

	last_overflow = hdr->overflows;

	/*

	 * the beginning of the buffer does not necessarily follow the header

	 * due to alignement.

	 */

	ent   = (smpl_entry_t *)((unsigned long)(hdr+1)+ hdr->start_offs);

	entry = collected_samples;

	while(count--) {

		printf("entry %06"PRIu64" eflags:0x%08lx EAX:0x%08lx ESP:0x%08lx IP:0x%08lx\n",

			entry,

			ent->eflags,

			ent->eax,

			ent->esp,

			ent->ip);

		ent++;

		entry++;

	}

	collected_samples = entry;

}

static int

get_cpuinfo_attr(char *attr, char *ret_buf, size_t maxlen)

{

	FILE *fp;

	int ret = -1;

	size_t attr_len, buf_len = 0;

	char *p, *value = NULL;

	char *buffer = NULL;

	if (attr == NULL || ret_buf == NULL || maxlen < 1)

		return -1;

	attr_len = strlen(attr);

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

	if (fp == NULL)

		return -1;

	while(getline(&buffer, &buf_len, fp) != -1){

		/* skip  blank lines */

		if (*buffer == '\n')

			continue;

		p = strchr(buffer, ':');

		if (p == NULL)

			goto error;

		/*

		 * p+2: +1 = space, +2= firt character

		 * strlen()-1 gets rid of \n

		 */

		*p = '\0';

		value = p+2;

		value[strlen(value)-1] = '\0';

		if (!strncmp(attr, buffer, attr_len))

			break;

	}

	strncpy(ret_buf, value, maxlen-1);

	ret_buf[maxlen-1] = '\0';

	ret = 0;

error:

	free(buffer);

	fclose(fp);

	return ret;

}

static void

check_valid_cpu(void)

{

	int ret, siblings, family, cores;

	char buffer[128];

	ret = get_cpuinfo_attr("vendor_id", buffer, sizeof(buffer));

	if (ret == -1 || strcmp(buffer, "GenuineIntel"))

		fatal_error("this programs works only with Intel processors\n");

	ret = get_cpuinfo_attr("cpu family", buffer, sizeof(buffer));

	if (ret == -1)

		fatal_error("cannot determine processor family\n");

	family = atoi(buffer);

	if (family != 15)

		fatal_error("this program only works for P4/Xeon with PEBS (found family=%d)\n", family);

	ret = get_cpuinfo_attr("siblings", buffer, sizeof(buffer));

	if (ret == -1)

		fatal_error("cannot deterimine number of siblings\n");

	siblings = atoi(buffer);

	ret = get_cpuinfo_attr("cpu cores", buffer, sizeof(buffer));

	if (ret == -1)

		fatal_error("cannot determine number of cpu cores\n");

	cores = atoi(buffer);

	if (siblings > cores)

		fatal_error("PEBS does not work when HyperThreading is enabled\n");

}

int

main(int argc, char **argv)

{

	pfarg_pmr_t pd[NUM_PMDS];

	pfarg_pmr_t pc[NUM_PMCS];

	smpl_arg_t buf_arg;

	pfarg_msg_t msg;

	smpl_hdr_t *hdr;

	void *buf_addr;

	pid_t pid;

	int ret, fd, status, npmcs = 0;

	check_valid_cpu();

	if (argc < 2)

		fatal_error("you need to pass a program to sample\n");

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

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

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

	buf_arg.buf_size = getpagesize();

	buf_arg.cnt_reset = -SMPL_PERIOD;

	/*

	 * trigger interrupt when reached 90% of buffer

	 */

	buf_arg.intr_thres = (buf_arg.buf_size/sizeof(smpl_entry_t))*90/100;

	fd = pfm_create(PFM_FL_SMPL_FMT, NULL, FMT_NAME, &buf_arg, sizeof(buf_arg));

	if (fd == -1) {

		if (errno == ENOSYS) {

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

		}

		fatal_error("cannot create session %s, maybe you do not have the P4/Xeon PEBS sampling format in the kernel.\n Check /sys/kernel/perfmon\n", strerror(errno));

	}

	/*

	 * retrieve the virtual address at which the sampling

	 * buffer has been mapped

	 */

	buf_addr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);

	if (buf_addr == MAP_FAILED)

		fatal_error("cannot mmap sampling buffer errno %d\n", errno);

	printf("session [%d] buffer mapped @%p\n", fd, buf_addr);

	hdr = (smpl_hdr_t *)buf_addr;

	printf("pebs_base=0x%lx pebs_end=0x%lx index=0x%lx\n"

	       "intr=0x%lx version=%u.%u\n"

	       "entry_size=%zu ds_size=%zu\n",

			hdr->ds.pebs_buf_base,

			hdr->ds.pebs_abs_max,

			hdr->ds.pebs_index,

			hdr->ds.pebs_intr_thres,

			PFM_VERSION_MAJOR(hdr->version),

			PFM_VERSION_MINOR(hdr->version),

			sizeof(smpl_entry_t),

			sizeof(hdr->ds));

	if (PFM_VERSION_MAJOR(hdr->version) < 1)

		fatal_error("invalid buffer format version\n");

	/*

	 * using the replay_event event

	 *

	 * CRU_ESCR2.usr=1

	 * CRU_ESCR2.event_mask=1 (NBOGUS)

	 * CRU_ESCR2.event_select=0x9 (replay_event)

	 */

	pc[npmcs].reg_num   = 21;

	pc[npmcs].reg_value = (9ULL <<25) | (1ULL<<9) |(1ULL<<2);

	npmcs++;

	/*

	 * for PEBS, must use IQ_CCCR4 for thread0

	 * IQ_CCCR4.escr_select = 5

	 * IQ_CCCR4.enable= 1

	 * IQ_CCCR4.active_thread= 3

	 *

	 * We must disable 64-bit emulation by the kernel

	 * on the associated counter when using PEBS. Otherwise

	 * we received a spurious interrupt for every counter overflow.

	 */

	pc[npmcs].reg_num   = 31;

	pc[npmcs].reg_flags = PFM_REGFL_NO_EMUL64;

	pc[npmcs].reg_value = (5ULL << 13) | (1ULL<<12) | (3ULL<<16);

	npmcs++;

	/*

	 * PEBS_MATRIX_VERT.bit0=1 (1st level cache load miss retired)

	 */

	pc[npmcs].reg_num   = 63;

	pc[npmcs].reg_value = 1;

	npmcs++;

	/*

	 * PEBS_ENABLE.enable=1 (bit0)

	 * PEBS_ENABLE.uops=1 (bit 24)

	 * PEBS_ENABLE.my_thr=1 (bit 25)

	 */

	pc[npmcs].reg_num   = 64;

	pc[npmcs].reg_value = (1ULL<<25)|(1ULL<<24) | 1ULL;

	npmcs++;

	/*

	 * Must use IQ_CCCR4/IQ_CTR4 with PEBS for thread0

	 *

	 * IMPORTANT:

	 * 	SMPL_PERIOD MUST not exceed width of HW counter

	 * 	because no 64-bit virtualization is done by the

	 * 	kernel.

	 */

	pd[0].reg_num = 8;

	pd[0].reg_flags = PFM_REGFL_OVFL_NOTIFY;

	pd[0].reg_value = -SMPL_PERIOD;

	/*

	 * Now program the registers

	 */

	if (pfm_write(fd, 0, PFM_RW_PMC, pc, npmcs * sizeof(*pc)) == -1)

		fatal_error("pfm_writeerror errno %d\n",errno);

	if (pfm_write(fd, 0, PFM_RW_PMD_ATTR, pd, sizeof(*pd)) == -1)

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

	signal(SIGCHLD, SIG_IGN);

	/*

	 * Create the child task

	 */

	if ((pid=fork()) == -1) fatal_error("Cannot fork process\n");

	/*

	 * In order to get the PFM_END_MSG message, it is important

	 * to ensure that the child task does not inherit the file

	 * descriptor of the session. By default, file descriptor

	 * are inherited during exec(). We explicitely close it

	 * here. We could have set it up through fcntl(FD_CLOEXEC)

	 * to achieve the same thing.

	 */

	if (pid == 0) {

		close(fd);

		child(argv+1);

	}

	/*

	 * wait for the child to exec

	 */

	waitpid(pid, &status, WUNTRACED);

	/*

	 * process is stopped at this point

	 */

	if (WIFEXITED(status)) {

		warning("task %s [%d] exited already status %d\n", argv[1], pid, WEXITSTATUS(status));

		goto terminate_session;

	}

	/*

	 *  attach the session

	 */

	if (pfm_attach(fd, 0, pid) == -1)

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

	/*

	 * start monitoring

	 */

	if (pfm_set_state(fd, 0, PFM_ST_START) == -1)

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

	/*

	 * detach child. Side effect includes

	 * activation of monitoring.

	 */

	ptrace(PTRACE_DETACH, pid, NULL, 0);

	/*

	 * core loop

	 */

	for(;;) {

		/*

		 * wait for overflow/end notification messages

		 */

		ret = read(fd, &msg, sizeof(msg));

		if (ret == -1) {

			if(ret == -1 && errno == EINTR) {

				warning("read interrupted, retrying\n");

				continue;

			}

			fatal_error("cannot read perfmon msg: %s\n", strerror(errno));

		}

		switch(msg.type) {

			case PFM_MSG_OVFL: /* the sampling buffer is full */

				process_smpl_buf(hdr);

				/*

				 * reactivate monitoring once we are done with the samples

				 *

				 * Note that this call can fail with EBUSY in non-blocking mode

				 * as the task may have disappeared while we were processing

				 * the samples.

				 */

				if (pfm_set_state(fd, 0, PFM_ST_RESTART) == -1) {

					if (errno != EBUSY)

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

					else

						warning("pfm_set_state(restart): task has probably terminated \n");

				}

				break;

			case PFM_MSG_END: /* monitored task terminated */

				warning("task terminated\n");

				goto terminate_session;

			default: fatal_error("unknown message type %d\n", msg.type);

		}

	}

terminate_session:

	/*

	 * cleanup child

	 */

	wait4(pid, &status, 0, NULL);

	/*

	 * check for any leftover samples

	 */

	process_smpl_buf(hdr);

	munmap(buf_addr, (size_t)buf_arg.buf_size);

	close(fd);

	return 0;

}