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/*
* Copyright (C) 2019 The Android Open Source Project
*
* 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.
*/
#include <fcntl.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <string>
#include "perfetto/base/logging.h"
#include "perfetto/base/time.h"
#include "perfetto/ext/base/file_utils.h"
#include "perfetto/ext/base/getopt.h"
#include "perfetto/ext/base/scoped_file.h"
// Periodically prints an un-normalized cpu usage ratio (full use of a single
// core = 1.0) of a target process. Based on /proc/pid/stat utime (userspace) &
// stime (kernel space).
namespace perfetto {
namespace {
uint64_t TimespecToMs(struct timespec ts) {
PERFETTO_CHECK(ts.tv_sec >= 0 && ts.tv_nsec >= 0);
return static_cast<uint64_t>(ts.tv_sec) * 1000 +
static_cast<uint64_t>(ts.tv_nsec) / 1000 / 1000;
}
uint64_t ReadWallTimeMs(clockid_t clk) {
struct timespec ts = {};
PERFETTO_CHECK(clock_gettime(clk, &ts) == 0);
return TimespecToMs(ts);
}
void ReadUtimeStime(const base::ScopedFile& stat_fd,
unsigned long* utime_out,
unsigned long* stime_out) {
char buf[1024] = {};
lseek(stat_fd.get(), 0, SEEK_SET);
PERFETTO_CHECK(read(stat_fd.get(), buf, sizeof(buf)) > 0);
buf[sizeof(buf) - 1] = '\0';
PERFETTO_CHECK(
sscanf(buf, "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %lu %lu",
utime_out, stime_out) == 2);
}
int CpuUtilizationMain(int argc, char** argv) {
unsigned sleep_duration_us = 10 * 1000 * 1000; // 10s
int sleep_intervals = 6;
int target_pid = -1;
static option long_options[] = {
{"pid", required_argument, nullptr, 'p'},
{"sleep-duration-us", required_argument, nullptr, 't'},
{"sleep-intervals", required_argument, nullptr, 'n'},
{nullptr, 0, nullptr, 0}};
int c;
while ((c = getopt_long(argc, argv, "", long_options, nullptr)) != -1) {
switch (c) {
case 'p':
target_pid = atoi(optarg);
break;
case 't':
sleep_duration_us = static_cast<unsigned>(atoi(optarg));
break;
case 'n':
sleep_intervals = atoi(optarg);
break;
default:
break;
}
}
if (target_pid < 1) {
PERFETTO_ELOG(
"Usage: %s --pid=target_pid [--sleep-duration-us=N] "
"[--sleep-intervals=N]",
argv[0]);
return 1;
}
// Resolution of utime/stime from procfs, at least 10 ms.
long ticks = sysconf(_SC_CLK_TCK);
PERFETTO_CHECK(ticks >= 100);
unsigned long ticks_per_s = static_cast<unsigned long>(ticks);
// Resolution of wallclock time, at least 1 ms. Should be O(ns) in practice.
auto clk = CLOCK_MONOTONIC_RAW;
struct timespec ts = {};
PERFETTO_CHECK(clock_getres(clk, &ts) == 0);
PERFETTO_CHECK(ts.tv_sec == 0 && ts.tv_nsec <= 1 * 1000 * 1000);
PERFETTO_LOG("--- setup: ---");
PERFETTO_LOG("target pid: %d", target_pid);
PERFETTO_LOG("intervals: %d x %uus", sleep_intervals, sleep_duration_us);
PERFETTO_LOG("utime/stime ticks per sec: %ld", ticks_per_s);
PERFETTO_LOG("wall clock resolution (ns): %ld", ts.tv_nsec);
PERFETTO_LOG("--- timings: ---");
base::ScopedFile fd = base::OpenFile(
std::string("/proc/") + std::to_string(target_pid) + std::string("/stat"),
O_RDONLY);
PERFETTO_CHECK(fd);
// Read the base times.
unsigned long first_utime = 0;
unsigned long first_stime = 0;
ReadUtimeStime(fd, &first_utime, &first_stime);
uint64_t first_walltime_ms = ReadWallTimeMs(clk);
uint64_t last_walltime_ms = first_walltime_ms;
unsigned long last_utime = first_utime;
unsigned long last_stime = first_stime;
// Report the utilization for each fixed duration chunk.
for (int i = 0; i < sleep_intervals; i++) {
base::SleepMicroseconds(sleep_duration_us);
unsigned long utime = 0;
unsigned long stime = 0;
ReadUtimeStime(fd, &utime, &stime);
uint64_t walltime_ms = ReadWallTimeMs(clk);
uint64_t wall_diff_ms = walltime_ms - last_walltime_ms;
PERFETTO_LOG("wall_ms : [%" PRIu64 "] - [%" PRIu64 "] = [%" PRIu64 "]",
walltime_ms, last_walltime_ms, wall_diff_ms);
unsigned long utime_diff = utime - last_utime;
unsigned long stime_diff = stime - last_stime;
PERFETTO_LOG("utime_ticks: [%lu] - [%lu] = [%lu]", utime, last_utime,
utime_diff);
PERFETTO_LOG("stime_ticks: [%lu] - [%lu] = [%lu]", stime, last_stime,
stime_diff);
// Calculate the utilization, resolution of inputs will be no worse than
// 10ms due to the above assert. At the default 10s wall time, we therefore
// get a resolution of at least 0.1%.
double utime_diff_ms = static_cast<double>(utime_diff * 1000 / ticks_per_s);
double stime_diff_ms = static_cast<double>(stime_diff * 1000 / ticks_per_s);
double utime_ratio = utime_diff_ms / static_cast<double>(wall_diff_ms);
double stime_ratio = stime_diff_ms / static_cast<double>(wall_diff_ms);
PERFETTO_LOG("utime ratio : %f", utime_ratio);
PERFETTO_LOG("stime ratio : %f", stime_ratio);
PERFETTO_LOG("combined ratio: %f\n", utime_ratio + stime_ratio);
last_walltime_ms = walltime_ms;
last_utime = utime;
last_stime = stime;
}
PERFETTO_LOG("--- timings over the whole period: ---");
unsigned long utime_diff = last_utime - first_utime;
unsigned long stime_diff = last_stime - first_stime;
uint64_t wall_diff_ms = last_walltime_ms - first_walltime_ms;
double utime_diff_ms = static_cast<double>(utime_diff * 1000 / ticks_per_s);
double stime_diff_ms = static_cast<double>(stime_diff * 1000 / ticks_per_s);
double utime_ratio = utime_diff_ms / static_cast<double>(wall_diff_ms);
double stime_ratio = stime_diff_ms / static_cast<double>(wall_diff_ms);
PERFETTO_LOG("utime ratio : %f", utime_ratio);
PERFETTO_LOG("stime ratio : %f", stime_ratio);
PERFETTO_LOG("combined ratio: %f\n", utime_ratio + stime_ratio);
return 0;
}
} // namespace
} // namespace perfetto
int main(int argc, char** argv) {
return perfetto::CpuUtilizationMain(argc, argv);
}