linux/tools/perf/builtin-record.c
Frederic Weisbecker 3928ddbe99 perf record: Fix unhandled io return value
Building latest perfcounter fails on the following error:

 builtin-record.c: In function ‘create_counter’:
 builtin-record.c:451: erreur: ignoring return value of ‘read’, declared with attribute warn_unused_result
 make: *** [builtin-record.o] Erreur 1

Just check if we successfully read the perf file descriptor.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1245961287-5327-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-25 22:25:55 +02:00

675 lines
14 KiB
C

/*
* builtin-record.c
*
* Builtin record command: Record the profile of a workload
* (or a CPU, or a PID) into the perf.data output file - for
* later analysis via perf report.
*/
#include "builtin.h"
#include "perf.h"
#include "util/util.h"
#include "util/parse-options.h"
#include "util/parse-events.h"
#include "util/string.h"
#include "util/header.h"
#include <unistd.h>
#include <sched.h>
#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a)-1)
#define __ALIGN_MASK(x, mask) (((x)+(mask))&~(mask))
static int fd[MAX_NR_CPUS][MAX_COUNTERS];
static long default_interval = 100000;
static int nr_cpus = 0;
static unsigned int page_size;
static unsigned int mmap_pages = 128;
static int freq = 0;
static int output;
static const char *output_name = "perf.data";
static int group = 0;
static unsigned int realtime_prio = 0;
static int system_wide = 0;
static pid_t target_pid = -1;
static int inherit = 1;
static int force = 0;
static int append_file = 0;
static int call_graph = 0;
static int verbose = 0;
static int inherit_stat = 0;
static int no_samples = 0;
static long samples;
static struct timeval last_read;
static struct timeval this_read;
static u64 bytes_written;
static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
static int nr_poll;
static int nr_cpu;
static int file_new = 1;
struct perf_header *header;
struct mmap_event {
struct perf_event_header header;
u32 pid;
u32 tid;
u64 start;
u64 len;
u64 pgoff;
char filename[PATH_MAX];
};
struct comm_event {
struct perf_event_header header;
u32 pid;
u32 tid;
char comm[16];
};
struct mmap_data {
int counter;
void *base;
unsigned int mask;
unsigned int prev;
};
static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
static unsigned long mmap_read_head(struct mmap_data *md)
{
struct perf_counter_mmap_page *pc = md->base;
long head;
head = pc->data_head;
rmb();
return head;
}
static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
{
struct perf_counter_mmap_page *pc = md->base;
/*
* ensure all reads are done before we write the tail out.
*/
/* mb(); */
pc->data_tail = tail;
}
static void write_output(void *buf, size_t size)
{
while (size) {
int ret = write(output, buf, size);
if (ret < 0)
die("failed to write");
size -= ret;
buf += ret;
bytes_written += ret;
}
}
static void mmap_read(struct mmap_data *md)
{
unsigned int head = mmap_read_head(md);
unsigned int old = md->prev;
unsigned char *data = md->base + page_size;
unsigned long size;
void *buf;
int diff;
gettimeofday(&this_read, NULL);
/*
* If we're further behind than half the buffer, there's a chance
* the writer will bite our tail and mess up the samples under us.
*
* If we somehow ended up ahead of the head, we got messed up.
*
* In either case, truncate and restart at head.
*/
diff = head - old;
if (diff < 0) {
struct timeval iv;
unsigned long msecs;
timersub(&this_read, &last_read, &iv);
msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
fprintf(stderr, "WARNING: failed to keep up with mmap data."
" Last read %lu msecs ago.\n", msecs);
/*
* head points to a known good entry, start there.
*/
old = head;
}
last_read = this_read;
if (old != head)
samples++;
size = head - old;
if ((old & md->mask) + size != (head & md->mask)) {
buf = &data[old & md->mask];
size = md->mask + 1 - (old & md->mask);
old += size;
write_output(buf, size);
}
buf = &data[old & md->mask];
size = head - old;
old += size;
write_output(buf, size);
md->prev = old;
mmap_write_tail(md, old);
}
static volatile int done = 0;
static volatile int signr = -1;
static void sig_handler(int sig)
{
done = 1;
signr = sig;
}
static void sig_atexit(void)
{
if (signr == -1)
return;
signal(signr, SIG_DFL);
kill(getpid(), signr);
}
static void pid_synthesize_comm_event(pid_t pid, int full)
{
struct comm_event comm_ev;
char filename[PATH_MAX];
char bf[BUFSIZ];
int fd;
size_t size;
char *field, *sep;
DIR *tasks;
struct dirent dirent, *next;
snprintf(filename, sizeof(filename), "/proc/%d/stat", pid);
fd = open(filename, O_RDONLY);
if (fd < 0) {
/*
* We raced with a task exiting - just return:
*/
if (verbose)
fprintf(stderr, "couldn't open %s\n", filename);
return;
}
if (read(fd, bf, sizeof(bf)) < 0) {
fprintf(stderr, "couldn't read %s\n", filename);
exit(EXIT_FAILURE);
}
close(fd);
/* 9027 (cat) R 6747 9027 6747 34816 9027 ... */
memset(&comm_ev, 0, sizeof(comm_ev));
field = strchr(bf, '(');
if (field == NULL)
goto out_failure;
sep = strchr(++field, ')');
if (sep == NULL)
goto out_failure;
size = sep - field;
memcpy(comm_ev.comm, field, size++);
comm_ev.pid = pid;
comm_ev.header.type = PERF_EVENT_COMM;
size = ALIGN(size, sizeof(u64));
comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
if (!full) {
comm_ev.tid = pid;
write_output(&comm_ev, comm_ev.header.size);
return;
}
snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
tasks = opendir(filename);
while (!readdir_r(tasks, &dirent, &next) && next) {
char *end;
pid = strtol(dirent.d_name, &end, 10);
if (*end)
continue;
comm_ev.tid = pid;
write_output(&comm_ev, comm_ev.header.size);
}
closedir(tasks);
return;
out_failure:
fprintf(stderr, "couldn't get COMM and pgid, malformed %s\n",
filename);
exit(EXIT_FAILURE);
}
static void pid_synthesize_mmap_samples(pid_t pid)
{
char filename[PATH_MAX];
FILE *fp;
snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
fp = fopen(filename, "r");
if (fp == NULL) {
/*
* We raced with a task exiting - just return:
*/
if (verbose)
fprintf(stderr, "couldn't open %s\n", filename);
return;
}
while (1) {
char bf[BUFSIZ], *pbf = bf;
struct mmap_event mmap_ev = {
.header.type = PERF_EVENT_MMAP,
};
int n;
size_t size;
if (fgets(bf, sizeof(bf), fp) == NULL)
break;
/* 00400000-0040c000 r-xp 00000000 fd:01 41038 /bin/cat */
n = hex2u64(pbf, &mmap_ev.start);
if (n < 0)
continue;
pbf += n + 1;
n = hex2u64(pbf, &mmap_ev.len);
if (n < 0)
continue;
pbf += n + 3;
if (*pbf == 'x') { /* vm_exec */
char *execname = strchr(bf, '/');
if (execname == NULL)
continue;
size = strlen(execname);
execname[size - 1] = '\0'; /* Remove \n */
memcpy(mmap_ev.filename, execname, size);
size = ALIGN(size, sizeof(u64));
mmap_ev.len -= mmap_ev.start;
mmap_ev.header.size = (sizeof(mmap_ev) -
(sizeof(mmap_ev.filename) - size));
mmap_ev.pid = pid;
mmap_ev.tid = pid;
write_output(&mmap_ev, mmap_ev.header.size);
}
}
fclose(fp);
}
static void synthesize_all(void)
{
DIR *proc;
struct dirent dirent, *next;
proc = opendir("/proc");
while (!readdir_r(proc, &dirent, &next) && next) {
char *end;
pid_t pid;
pid = strtol(dirent.d_name, &end, 10);
if (*end) /* only interested in proper numerical dirents */
continue;
pid_synthesize_comm_event(pid, 1);
pid_synthesize_mmap_samples(pid);
}
closedir(proc);
}
static int group_fd;
static struct perf_header_attr *get_header_attr(struct perf_counter_attr *a, int nr)
{
struct perf_header_attr *h_attr;
if (nr < header->attrs) {
h_attr = header->attr[nr];
} else {
h_attr = perf_header_attr__new(a);
perf_header__add_attr(header, h_attr);
}
return h_attr;
}
static void create_counter(int counter, int cpu, pid_t pid)
{
struct perf_counter_attr *attr = attrs + counter;
struct perf_header_attr *h_attr;
int track = !counter; /* only the first counter needs these */
struct {
u64 count;
u64 time_enabled;
u64 time_running;
u64 id;
} read_data;
attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
PERF_FORMAT_TOTAL_TIME_RUNNING |
PERF_FORMAT_ID;
attr->sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
if (freq) {
attr->sample_type |= PERF_SAMPLE_PERIOD;
attr->freq = 1;
attr->sample_freq = freq;
}
if (no_samples)
attr->sample_freq = 0;
if (inherit_stat)
attr->inherit_stat = 1;
if (call_graph)
attr->sample_type |= PERF_SAMPLE_CALLCHAIN;
attr->mmap = track;
attr->comm = track;
attr->inherit = (cpu < 0) && inherit;
attr->disabled = 1;
try_again:
fd[nr_cpu][counter] = sys_perf_counter_open(attr, pid, cpu, group_fd, 0);
if (fd[nr_cpu][counter] < 0) {
int err = errno;
if (err == EPERM)
die("Permission error - are you root?\n");
/*
* If it's cycles then fall back to hrtimer
* based cpu-clock-tick sw counter, which
* is always available even if no PMU support:
*/
if (attr->type == PERF_TYPE_HARDWARE
&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {
if (verbose)
warning(" ... trying to fall back to cpu-clock-ticks\n");
attr->type = PERF_TYPE_SOFTWARE;
attr->config = PERF_COUNT_SW_CPU_CLOCK;
goto try_again;
}
printf("\n");
error("perfcounter syscall returned with %d (%s)\n",
fd[nr_cpu][counter], strerror(err));
die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
exit(-1);
}
h_attr = get_header_attr(attr, counter);
if (!file_new) {
if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
fprintf(stderr, "incompatible append\n");
exit(-1);
}
}
if (read(fd[nr_cpu][counter], &read_data, sizeof(read_data)) == -1) {
perror("Unable to read perf file descriptor\n");
exit(-1);
}
perf_header_attr__add_id(h_attr, read_data.id);
assert(fd[nr_cpu][counter] >= 0);
fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
/*
* First counter acts as the group leader:
*/
if (group && group_fd == -1)
group_fd = fd[nr_cpu][counter];
event_array[nr_poll].fd = fd[nr_cpu][counter];
event_array[nr_poll].events = POLLIN;
nr_poll++;
mmap_array[nr_cpu][counter].counter = counter;
mmap_array[nr_cpu][counter].prev = 0;
mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter], 0);
if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
error("failed to mmap with %d (%s)\n", errno, strerror(errno));
exit(-1);
}
ioctl(fd[nr_cpu][counter], PERF_COUNTER_IOC_ENABLE);
}
static void open_counters(int cpu, pid_t pid)
{
int counter;
group_fd = -1;
for (counter = 0; counter < nr_counters; counter++)
create_counter(counter, cpu, pid);
nr_cpu++;
}
static void atexit_header(void)
{
header->data_size += bytes_written;
perf_header__write(header, output);
}
static int __cmd_record(int argc, const char **argv)
{
int i, counter;
struct stat st;
pid_t pid = 0;
int flags;
int ret;
page_size = sysconf(_SC_PAGE_SIZE);
nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
assert(nr_cpus <= MAX_NR_CPUS);
assert(nr_cpus >= 0);
atexit(sig_atexit);
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
if (!stat(output_name, &st) && !force && !append_file) {
fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
output_name);
exit(-1);
}
flags = O_CREAT|O_RDWR;
if (append_file)
file_new = 0;
else
flags |= O_TRUNC;
output = open(output_name, flags, S_IRUSR|S_IWUSR);
if (output < 0) {
perror("failed to create output file");
exit(-1);
}
if (!file_new)
header = perf_header__read(output);
else
header = perf_header__new();
atexit(atexit_header);
if (!system_wide) {
pid = target_pid;
if (pid == -1)
pid = getpid();
open_counters(-1, pid);
} else for (i = 0; i < nr_cpus; i++)
open_counters(i, target_pid);
if (file_new)
perf_header__write(header, output);
if (!system_wide) {
pid_synthesize_comm_event(pid, 0);
pid_synthesize_mmap_samples(pid);
} else
synthesize_all();
if (target_pid == -1 && argc) {
pid = fork();
if (pid < 0)
perror("failed to fork");
if (!pid) {
if (execvp(argv[0], (char **)argv)) {
perror(argv[0]);
exit(-1);
}
}
}
if (realtime_prio) {
struct sched_param param;
param.sched_priority = realtime_prio;
if (sched_setscheduler(0, SCHED_FIFO, &param)) {
printf("Could not set realtime priority.\n");
exit(-1);
}
}
for (;;) {
int hits = samples;
for (i = 0; i < nr_cpu; i++) {
for (counter = 0; counter < nr_counters; counter++)
mmap_read(&mmap_array[i][counter]);
}
if (hits == samples) {
if (done)
break;
ret = poll(event_array, nr_poll, 100);
}
}
/*
* Approximate RIP event size: 24 bytes.
*/
fprintf(stderr,
"[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
(double)bytes_written / 1024.0 / 1024.0,
output_name,
bytes_written / 24);
return 0;
}
static const char * const record_usage[] = {
"perf record [<options>] [<command>]",
"perf record [<options>] -- <command> [<options>]",
NULL
};
static const struct option options[] = {
OPT_CALLBACK('e', "event", NULL, "event",
"event selector. use 'perf list' to list available events",
parse_events),
OPT_INTEGER('p', "pid", &target_pid,
"record events on existing pid"),
OPT_INTEGER('r', "realtime", &realtime_prio,
"collect data with this RT SCHED_FIFO priority"),
OPT_BOOLEAN('a', "all-cpus", &system_wide,
"system-wide collection from all CPUs"),
OPT_BOOLEAN('A', "append", &append_file,
"append to the output file to do incremental profiling"),
OPT_BOOLEAN('f', "force", &force,
"overwrite existing data file"),
OPT_LONG('c', "count", &default_interval,
"event period to sample"),
OPT_STRING('o', "output", &output_name, "file",
"output file name"),
OPT_BOOLEAN('i', "inherit", &inherit,
"child tasks inherit counters"),
OPT_INTEGER('F', "freq", &freq,
"profile at this frequency"),
OPT_INTEGER('m', "mmap-pages", &mmap_pages,
"number of mmap data pages"),
OPT_BOOLEAN('g', "call-graph", &call_graph,
"do call-graph (stack chain/backtrace) recording"),
OPT_BOOLEAN('v', "verbose", &verbose,
"be more verbose (show counter open errors, etc)"),
OPT_BOOLEAN('s', "stat", &inherit_stat,
"per thread counts"),
OPT_BOOLEAN('n', "no-samples", &no_samples,
"don't sample"),
OPT_END()
};
int cmd_record(int argc, const char **argv, const char *prefix)
{
int counter;
argc = parse_options(argc, argv, options, record_usage, 0);
if (!argc && target_pid == -1 && !system_wide)
usage_with_options(record_usage, options);
if (!nr_counters) {
nr_counters = 1;
attrs[0].type = PERF_TYPE_HARDWARE;
attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
}
for (counter = 0; counter < nr_counters; counter++) {
if (attrs[counter].sample_period)
continue;
attrs[counter].sample_period = default_interval;
}
return __cmd_record(argc, argv);
}