int *fd_group_init(int num_events, char **events) {
struct perf_event_attr *attr;
int fd, ret, leader_fd, i;
int *fds = malloc(num_events * sizeof(int));
if (!fds) err(1, "could not allocate memory");
attr = calloc(num_events, sizeof(*attr));
// do refs, then misses
for (i = 0; i < num_events; i++) {
/*
* 1st argument: event string
* 2nd argument: default privilege level (used if not specified in the event string)
* 3rd argument: the perf_event_attr to initialize
*/
ret = pfm_get_perf_event_encoding(events[i], PFM_PLM3, &attr[i], NULL, NULL);
if (ret != PFM_SUCCESS) errx(1, "evt %d: cannot find encoding: %s", i, pfm_strerror(ret));
printf("Using encoding %lx for event %s\n", attr[i].config, events[i]);
attr[i].inherit = 0; // inheritance currently doesn't work with FORMAT_GROUP
/*
* request timing information because event may be multiplexed
* and thus it may not count all the time. The scaling information
* will be used to scale the raw count as if the event had run all
* along
*/
attr[i].read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING
| PERF_FORMAT_GROUP;
/* do not start immediately after perf_event_open() */
attr[i].disabled = 1;
/*
* create the event and attach to self
* Note that it attaches only to the main thread, there is no inheritance
* to threads that may be created subsequently.
*
* if mulithreaded, then getpid() must be replaced by gettid()
*/
if (i == 0) {
fd = perf_event_open(&attr[i], 0, -1, -1, 0);
fds[i] = fd;
leader_fd = fd;
} else {
fd = perf_event_open(&attr[i], 0, -1, leader_fd, 0);
fds[i] = fd;
}
if (fd < 0) {
warn("warning: evt %d: cannot create event", i);
free(attr);
free(fds);
return NULL;
}
}
free(attr);
return fds;
}
EXTERNAL void sysPerfEventCreate(int id, const char *eventName)
{
TRACE_PRINTF("%s: sysPerfEventCreate\n", Me);
struct perf_event_attr *pe = (perf_event_attrs + id);
int ret = pfm_get_perf_event_encoding(eventName, PFM_PLM3, pe, NULL, NULL);
if (ret != PFM_SUCCESS) {
errx(1, "error creating event %d '%s': %s\n", id, eventName, pfm_strerror(ret));
}
pe->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING;
pe->disabled = 1;
pe->inherit = 1;
perf_event_fds[id] = perf_event_open(pe, 0, -1, -1, 0);
if (perf_event_fds[id] == -1) {
err(1, "error in perf_event_open for event %d '%s'", id, eventName);
}
}
bool pfm_instance::event_encoding(const std::string& event, unsigned int& type, unsigned long long& config)
{
int ret;
struct perf_event_attr attr;
memset(&attr, 0, sizeof(attr));
ret = pfm_get_perf_event_encoding(event.c_str(), PFM_PLM3, &attr, NULL, NULL);
if (ret != PFM_SUCCESS)
{
type = 0;
config = 0;
return false;
}
type = attr.type;
config = attr.config;
return true;
}
int
main(int argc, char **argv)
{
struct perf_event_attr attr;
int fd, ret;
uint64_t count = 0, values[3];
setlocale(LC_ALL, "");
/*
* Initialize libpfm library (required before we can use it)
*/
ret = pfm_initialize();
if (ret != PFM_SUCCESS)
errx(1, "cannot initialize library: %s", pfm_strerror(ret));
memset(&attr, 0, sizeof(attr));
/*
* 1st argument: event string
* 2nd argument: default privilege level (used if not specified in the event string)
* 3rd argument: the perf_event_attr to initialize
*/
ret = pfm_get_perf_event_encoding("cycles", PFM_PLM0|PFM_PLM3, &attr, NULL, NULL);
if (ret != PFM_SUCCESS)
errx(1, "cannot find encoding: %s", pfm_strerror(ret));
/*
* request timing information because event may be multiplexed
* and thus it may not count all the time. The scaling information
* will be used to scale the raw count as if the event had run all
* along
*/
attr.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING;
/* do not start immediately after perf_event_open() */
attr.disabled = 1;
/*
* create the event and attach to self
* Note that it attaches only to the main thread, there is no inheritance
* to threads that may be created subsequently.
*
* if mulithreaded, then getpid() must be replaced by gettid()
*/
fd = perf_event_open(&attr, getpid(), -1, -1, 0);
if (fd < 0)
err(1, "cannot create event");
/*
* start counting now
*/
ret = ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);
if (ret)
err(1, "ioctl(enable) failed");
printf("Fibonacci(%d)=%lu\n", N, fib(N));
/*
* stop counting
*/
ret = ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
if (ret)
err(1, "ioctl(disable) failed");
/*
* read the count + scaling values
*
* It is not necessary to stop an event to read its value
*/
ret = read(fd, values, sizeof(values));
if (ret != sizeof(values))
err(1, "cannot read results: %s", strerror(errno));
/*
* scale count
*
* values[0] = raw count
* values[1] = TIME_ENABLED
* values[2] = TIME_RUNNING
*/
if (values[2])
count = (uint64_t)((double)values[0] * values[1]/values[2]);
printf("count=%'"PRIu64"\n", count);
close(fd);
/* free libpfm resources cleanly */
pfm_terminate();
return 0;
}
