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/*
* Copyright (c) 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This implementation only applies to the Linux platform. */
#include <config.h>
#if defined(__linux__) && defined(HAVE_LINUX_PERF_EVENT_H)
#include <stddef.h>
#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <asm/unistd.h>
#include "dynamic-string.h"
#include "openvswitch/vlog.h"
#include "perf-counter.h"
#include "shash.h"
#include "util.h"
VLOG_DEFINE_THIS_MODULE(perf_counter);
static struct shash perf_counters;
static int fd__ = 0;
uint64_t
perf_counter_read(uint64_t *counter)
{
int size = sizeof *counter;
if (fd__ <= 0 || read(fd__, counter, size) < size) {
*counter = 0;
}
return *counter;
}
static long
perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
int cpu, int group_fd, unsigned long flags)
{
int ret;
ret = syscall(__NR_perf_event_open, hw_event, pid, cpu,
group_fd, flags);
return ret;
}
/* Set up perf event counters to read user space instruction counters
* only for this process, on all cpus. */
static void
perf_event_setup(void)
{
struct perf_event_attr pe;
memset(&pe, 0, sizeof(struct perf_event_attr));
pe.type = PERF_TYPE_HARDWARE;
pe.size = sizeof(struct perf_event_attr);
pe.config = PERF_COUNT_HW_INSTRUCTIONS;
pe.disabled = 1;
pe.exclude_kernel = 1;
pe.exclude_hv = 1;
fd__ = perf_event_open(&pe, 0, -1, -1, 0);
if (fd__ > 0) {
ioctl(fd__, PERF_EVENT_IOC_RESET, 0);
ioctl(fd__, PERF_EVENT_IOC_ENABLE, 0);
}
}
static void
perf_counter_init(struct perf_counter *counter)
{
counter->once = true;
shash_add_assert(&perf_counters, counter->name, counter);
}
void
perf_counter_accumulate(struct perf_counter *counter, uint64_t start_count)
{
uint64_t end_count;
if (!counter->once) {
perf_counter_init(counter);
}
counter->n_events++;
perf_counter_read(&end_count);
counter->total_count += end_count - start_count;
}
static void
perf_counter_to_ds(struct ds *ds, struct perf_counter *pfc)
{
double ratio;
if (pfc->n_events) {
ratio = (double)pfc->total_count / (double)pfc->n_events;
} else {
ratio = 0.0;
}
ds_put_format(ds, "%-40s%12"PRIu64"%12"PRIu64"%12.1f\n",
pfc->name, pfc->n_events, pfc->total_count, ratio);
}
static void
perf_counters_to_ds(struct ds *ds)
{
const char *err_str;
const struct shash_node **sorted;
int i;
err_str = NULL;
if (fd__ == -1) {
err_str = "performance counter is not supported on this platfrom";
} else if (!shash_count(&perf_counters)) {
err_str = "performance counter has never been hit";
}
if (err_str) {
ds_put_format(ds, "%s\n", err_str);
return;
}
/* Display counters in alphabetical order. */
sorted = shash_sort(&perf_counters);
for (i = 0; i < shash_count(&perf_counters); i++) {
perf_counter_to_ds(ds, sorted[i]->data);
}
free(sorted);
}
/*
* Caller is responsible for free memory.
*/
char *
perf_counters_to_string()
{
struct ds ds;
ds_init(&ds);
perf_counters_to_ds(&ds);
return ds_steal_cstr(&ds);
}
void
perf_counters_init(void)
{
shash_init(&perf_counters);
perf_event_setup();
}
void
perf_counters_clear(void)
{
struct shash_node *node;
SHASH_FOR_EACH (node, &perf_counters) {
struct perf_counter *perf = node->data;
perf->n_events = 0;
perf->total_count = 0;
}
}
void
perf_counters_destroy()
{
struct shash_node *node, *next;
if (fd__ != -1) {
ioctl(fd__, PERF_EVENT_IOC_DISABLE, 0);
close(fd__);
}
SHASH_FOR_EACH_SAFE (node, next, &perf_counters) {
shash_delete(&perf_counters, node);
}
shash_destroy(&perf_counters);
}
#endif
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