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/*
* 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 sz, 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)
{
uint64_t *val;
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;
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 (num_fds > 1)
fds[i].hw.read_format |= PERF_FORMAT_GROUP|PERF_FORMAT_ID;
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");
}
/*
* we are using PERF_FORMAT_GROUP, therefore the structure
* of val is as follows:
*
* { u64 nr;
* { u64 time_enabled; } && PERF_FORMAT_ENABLED
* { u64 time_running; } && PERF_FORMAT_RUNNING
* { u64 value;
* { u64 id; } && PERF_FORMAT_ID
* } cntr[nr];
* }
* We are skipping the first 3 values (nr, time_enabled, time_running)
* and then for each event we get a pair of values.
*/
if (num_fds > 1 && fds[0].fd > -1) {
ssize_t sret;
sz = (3+2*num_fds)*sizeof(uint64_t);
val = malloc(sz);
if (!val)
err(1, "cannot allocated memory");
sret = read(fds[0].fd, val, sz);
if (sret == (ssize_t)sz)
err(1, "cannot read id %zu", sizeof(val));
for(i=0; i < num_fds; i++) {
fds[i].id = val[2*i+1+3];
printf("%"PRIu64" %s\n", fds[i].id, fds[i].name);
}
free(val);
}
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 const char
*cgroupfs_find_mountpoint(void)
{
static char cgroup_mountpoint[MAX_PATH+1];
FILE *fp;
int found = 0;
char type[64];
fp = fopen("/proc/mounts", "r");
if (!fp)
return NULL;
while (fscanf(fp, "%*s %"
STR(MAX_PATH)
"s %99s %*s %*d %*d\n",
cgroup_mountpoint, type) == 2) {
found = !strcmp(type, "cgroup");
if (found)
break;
}
fclose(fp);
return found ? cgroup_mountpoint : NULL;
}
int
open_cgroup(char *name)
{
char path[MAX_PATH+1];
const char *mnt;
int cfd;
mnt = cgroupfs_find_mountpoint();
if (!mnt)
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);
}

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