// Copyright 2015 Google Inc. All rights reserved.
//
// 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 "sysinfo.h"
#include "internal_macros.h"
#ifdef BENCHMARK_OS_WINDOWS
#include <Shlwapi.h>
#include <VersionHelpers.h>
#include <Windows.h>
#else
#include <fcntl.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/types.h> // this header must be included before 'sys/sysctl.h' to avoid compilation error on FreeBSD
#include <unistd.h>
#if defined BENCHMARK_OS_FREEBSD || defined BENCHMARK_OS_MACOSX
#include <sys/sysctl.h>
#endif
#endif
#include <cerrno>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <limits>
#include <mutex>
#include "arraysize.h"
#include "check.h"
#include "cycleclock.h"
#include "internal_macros.h"
#include "log.h"
#include "sleep.h"
#include "string_util.h"
namespace benchmark {
namespace {
std::once_flag cpuinfo_init;
double cpuinfo_cycles_per_second = 1.0;
int cpuinfo_num_cpus = 1; // Conservative guess
#if !defined BENCHMARK_OS_MACOSX
const int64_t estimate_time_ms = 1000;
// Helper function estimates cycles/sec by observing cycles elapsed during
// sleep(). Using small sleep time decreases accuracy significantly.
int64_t EstimateCyclesPerSecond() {
const int64_t start_ticks = cycleclock::Now();
SleepForMilliseconds(estimate_time_ms);
return cycleclock::Now() - start_ticks;
}
#endif
#if defined BENCHMARK_OS_LINUX || defined BENCHMARK_OS_CYGWIN
// Helper function for reading an int from a file. Returns true if successful
// and the memory location pointed to by value is set to the value read.
bool ReadIntFromFile(const char* file, long* value) {
bool ret = false;
int fd = open(file, O_RDONLY);
if (fd != -1) {
char line[1024];
char* err;
memset(line, '\0', sizeof(line));
CHECK(read(fd, line, sizeof(line) - 1));
const long temp_value = strtol(line, &err, 10);
if (line[0] != '\0' && (*err == '\n' || *err == '\0')) {
*value = temp_value;
ret = true;
}
close(fd);
}
return ret;
}
#endif
#if defined BENCHMARK_OS_LINUX || defined BENCHMARK_OS_CYGWIN
static std::string convertToLowerCase(std::string s) {
for (auto& ch : s)
ch = std::tolower(ch);
return s;
}
static bool startsWithKey(std::string Value, std::string Key,
bool IgnoreCase = true) {
if (IgnoreCase) {
Key = convertToLowerCase(std::move(Key));
Value = convertToLowerCase(std::move(Value));
}
return Value.compare(0, Key.size(), Key) == 0;
}
#endif
void InitializeSystemInfo() {
#if defined BENCHMARK_OS_LINUX || defined BENCHMARK_OS_CYGWIN
char line[1024];
char* err;
long freq;
bool saw_mhz = false;
// If the kernel is exporting the tsc frequency use that. There are issues
// where cpuinfo_max_freq cannot be relied on because the BIOS may be
// exporintg an invalid p-state (on x86) or p-states may be used to put the
// processor in a new mode (turbo mode). Essentially, those frequencies
// cannot always be relied upon. The same reasons apply to /proc/cpuinfo as
// well.
if (!saw_mhz &&
ReadIntFromFile("/sys/devices/system/cpu/cpu0/tsc_freq_khz", &freq)) {
// The value is in kHz (as the file name suggests). For example, on a
// 2GHz warpstation, the file contains the value "2000000".
cpuinfo_cycles_per_second = freq * 1000.0;
saw_mhz = true;
}
// If CPU scaling is in effect, we want to use the *maximum* frequency,
// not whatever CPU speed some random processor happens to be using now.
if (!saw_mhz &&
ReadIntFromFile("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq",
&freq)) {
// The value is in kHz. For example, on a 2GHz warpstation, the file
// contains the value "2000000".
cpuinfo_cycles_per_second = freq * 1000.0;
saw_mhz = true;
}
// Read /proc/cpuinfo for other values, and if there is no cpuinfo_max_freq.
const char* pname = "/proc/cpuinfo";
int fd = open(pname, O_RDONLY);
if (fd == -1) {
perror(pname);
if (!saw_mhz) {
cpuinfo_cycles_per_second =
static_cast<double>(EstimateCyclesPerSecond());
}
return;
}
double bogo_clock = 1.0;
bool saw_bogo = false;
long max_cpu_id = 0;
int num_cpus = 0;
line[0] = line[1] = '\0';
size_t chars_read = 0;
do { // we'll exit when the last read didn't read anything
// Move the next line to the beginning of the buffer
const size_t oldlinelen = strlen(line);
if (sizeof(line) == oldlinelen + 1) // oldlinelen took up entire line
line[0] = '\0';
else // still other lines left to save
memmove(line, line + oldlinelen + 1, sizeof(line) - (oldlinelen + 1));
// Terminate the new line, reading more if we can't find the newline
char* newline = strchr(line, '\n');
if (newline == nullptr) {
const size_t linelen = strlen(line);
const size_t bytes_to_read = sizeof(line) - 1 - linelen;
CHECK(bytes_to_read > 0); // because the memmove recovered >=1 bytes
chars_read = read(fd, line + linelen, bytes_to_read);
line[linelen + chars_read] = '\0';
newline = strchr(line, '\n');
}
if (newline != nullptr) *newline = '\0';
// When parsing the "cpu MHz" and "bogomips" (fallback) entries, we only
// accept postive values. Some environments (virtual machines) report zero,
// which would cause infinite looping in WallTime_Init.
if (!saw_mhz && startsWithKey(line, "cpu MHz")) {
const char* freqstr = strchr(line, ':');
if (freqstr) {
cpuinfo_cycles_per_second = strtod(freqstr + 1, &err) * 1000000.0;
if (freqstr[1] != '\0' && *err == '\0' && cpuinfo_cycles_per_second > 0)
saw_mhz = true;
}
} else if (startsWithKey(line, "bogomips")) {
const char* freqstr = strchr(line, ':');
if (freqstr) {
bogo_clock = strtod(freqstr + 1, &err) * 1000000.0;
if (freqstr[1] != '\0' && *err == '\0' && bogo_clock > 0)
saw_bogo = true;
}
} else if (startsWithKey(line, "processor", /*IgnoreCase*/false)) {
// The above comparison is case-sensitive because ARM kernels often
// include a "Processor" line that tells you about the CPU, distinct
// from the usual "processor" lines that give you CPU ids. No current
// Linux architecture is using "Processor" for CPU ids.
num_cpus++; // count up every time we see an "processor :" entry
const char* id_str = strchr(line, ':');
if (id_str) {
const long cpu_id = strtol(id_str + 1, &err, 10);
if (id_str[1] != '\0' && *err == '\0' && max_cpu_id < cpu_id)
max_cpu_id = cpu_id;
}
}
} while (chars_read > 0);
close(fd);
if (!saw_mhz) {
if (saw_bogo) {
// If we didn't find anything better, we'll use bogomips, but
// we're not happy about it.
cpuinfo_cycles_per_second = bogo_clock;
} else {
// If we don't even have bogomips, we'll use the slow estimation.
cpuinfo_cycles_per_second =
static_cast<double>(EstimateCyclesPerSecond());
}
}
if (num_cpus == 0) {
fprintf(stderr, "Failed to read num. CPUs correctly from /proc/cpuinfo\n");
} else {
if ((max_cpu_id + 1) != num_cpus) {
fprintf(stderr,
"CPU ID assignments in /proc/cpuinfo seem messed up."
" This is usually caused by a bad BIOS.\n");
}
cpuinfo_num_cpus = num_cpus;
}
#elif defined BENCHMARK_OS_FREEBSD
// For this sysctl to work, the machine must be configured without
// SMP, APIC, or APM support. hz should be 64-bit in freebsd 7.0
// and later. Before that, it's a 32-bit quantity (and gives the
// wrong answer on machines faster than 2^32 Hz). See
// http://lists.freebsd.org/pipermail/freebsd-i386/2004-November/001846.html
// But also compare FreeBSD 7.0:
// http://fxr.watson.org/fxr/source/i386/i386/tsc.c?v=RELENG70#L223
// 231 error = sysctl_handle_quad(oidp, &freq, 0, req);
// To FreeBSD 6.3 (it's the same in 6-STABLE):
// http://fxr.watson.org/fxr/source/i386/i386/tsc.c?v=RELENG6#L131
// 139 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
#if __FreeBSD__ >= 7
uint64_t hz = 0;
#else
unsigned int hz = 0;
#endif
size_t sz = sizeof(hz);
const char* sysctl_path = "machdep.tsc_freq";
if (sysctlbyname(sysctl_path, &hz, &sz, nullptr, 0) != 0) {
fprintf(stderr, "Unable to determine clock rate from sysctl: %s: %s\n",
sysctl_path, strerror(errno));
cpuinfo_cycles_per_second = static_cast<double>(EstimateCyclesPerSecond());
} else {
cpuinfo_cycles_per_second = hz;
}
// TODO: also figure out cpuinfo_num_cpus
#elif defined BENCHMARK_OS_WINDOWS
// In NT, read MHz from the registry. If we fail to do so or we're in win9x
// then make a crude estimate.
DWORD data, data_size = sizeof(data);
if (IsWindowsXPOrGreater() &&
SUCCEEDED(
SHGetValueA(HKEY_LOCAL_MACHINE,
"HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0",
"~MHz", nullptr, &data, &data_size)))
cpuinfo_cycles_per_second =
static_cast<double>((int64_t)data * (int64_t)(1000 * 1000)); // was mhz
else
cpuinfo_cycles_per_second = static_cast<double>(EstimateCyclesPerSecond());
SYSTEM_INFO sysinfo;
// Use memset as opposed to = {} to avoid GCC missing initializer false
// positives.
std::memset(&sysinfo, 0, sizeof(SYSTEM_INFO));
GetSystemInfo(&sysinfo);
cpuinfo_num_cpus = sysinfo.dwNumberOfProcessors; // number of logical
// processors in the current
// group
#elif defined BENCHMARK_OS_MACOSX
int32_t num_cpus = 0;
size_t size = sizeof(num_cpus);
if (::sysctlbyname("hw.ncpu", &num_cpus, &size, nullptr, 0) == 0 &&
(size == sizeof(num_cpus))) {
cpuinfo_num_cpus = num_cpus;
} else {
fprintf(stderr, "%s\n", strerror(errno));
std::exit(EXIT_FAILURE);
}
int64_t cpu_freq = 0;
size = sizeof(cpu_freq);
if (::sysctlbyname("hw.cpufrequency", &cpu_freq, &size, nullptr, 0) == 0 &&
(size == sizeof(cpu_freq))) {
cpuinfo_cycles_per_second = cpu_freq;
} else {
fprintf(stderr, "%s\n", strerror(errno));
std::exit(EXIT_FAILURE);
}
#else
// Generic cycles per second counter
cpuinfo_cycles_per_second = static_cast<double>(EstimateCyclesPerSecond());
#endif
}
} // end namespace
double CyclesPerSecond(void) {
std::call_once(cpuinfo_init, InitializeSystemInfo);
return cpuinfo_cycles_per_second;
}
int NumCPUs(void) {
std::call_once(cpuinfo_init, InitializeSystemInfo);
return cpuinfo_num_cpus;
}
// The ""'s catch people who don't pass in a literal for "str"
#define strliterallen(str) (sizeof("" str "") - 1)
// Must use a string literal for prefix.
#define memprefix(str, len, prefix) \
((((len) >= strliterallen(prefix)) && \
std::memcmp(str, prefix, strliterallen(prefix)) == 0) \
? str + strliterallen(prefix) \
: nullptr)
bool CpuScalingEnabled() {
#ifndef BENCHMARK_OS_WINDOWS
// On Linux, the CPUfreq subsystem exposes CPU information as files on the
// local file system. If reading the exported files fails, then we may not be
// running on Linux, so we silently ignore all the read errors.
for (int cpu = 0, num_cpus = NumCPUs(); cpu < num_cpus; ++cpu) {
std::string governor_file =
StrCat("/sys/devices/system/cpu/cpu", cpu, "/cpufreq/scaling_governor");
FILE* file = fopen(governor_file.c_str(), "r");
if (!file) break;
char buff[16];
size_t bytes_read = fread(buff, 1, sizeof(buff), file);
fclose(file);
if (memprefix(buff, bytes_read, "performance") == nullptr) return true;
}
#endif
return false;
}
} // end namespace benchmark