diff options
| -rw-r--r-- | src/base/spinlock.cc | 4 | ||||
| -rw-r--r-- | src/base/sysinfo.cc | 310 | ||||
| -rw-r--r-- | src/base/sysinfo.h | 6 |
3 files changed, 12 insertions, 308 deletions
diff --git a/src/base/spinlock.cc b/src/base/spinlock.cc index 9fda1bb..8b1f11f 100644 --- a/src/base/spinlock.cc +++ b/src/base/spinlock.cc @@ -35,7 +35,7 @@ #include <config.h> #include "base/spinlock.h" #include "base/spinlock_internal.h" -#include "base/sysinfo.h" /* for NumCPUs() */ +#include "base/sysinfo.h" /* for GetSystemCPUsCount() */ // NOTE on the Lock-state values: // @@ -53,7 +53,7 @@ struct SpinLock_InitHelper { SpinLock_InitHelper() { // On multi-cpu machines, spin for longer before yielding // the processor or sleeping. Reduces idle time significantly. - if (NumCPUs() > 1) { + if (GetSystemCPUsCount() > 1) { adaptive_spin_count = 1000; } } diff --git a/src/base/sysinfo.cc b/src/base/sysinfo.cc index cad751b..7b01e4c 100644 --- a/src/base/sysinfo.cc +++ b/src/base/sysinfo.cc @@ -212,17 +212,6 @@ bool GetUniquePathFromEnv(const char* env_name, char* path) { return true; } -// ---------------------------------------------------------------------- -// CyclesPerSecond() -// NumCPUs() -// It's important this not call malloc! -- they may be called at -// global-construct time, before we've set up all our proper malloc -// hooks and such. -// ---------------------------------------------------------------------- - -static double cpuinfo_cycles_per_second = 1.0; // 0.0 might be dangerous -static int cpuinfo_num_cpus = 1; // Conservative guess - void SleepForMilliseconds(int milliseconds) { #ifdef PLATFORM_WINDOWS _sleep(milliseconds); // Windows's _sleep takes milliseconds argument @@ -236,301 +225,20 @@ void SleepForMilliseconds(int milliseconds) { #endif } -// Helper function estimates cycles/sec by observing cycles elapsed during -// sleep(). Using small sleep time decreases accuracy significantly. -static int64 EstimateCyclesPerSecond(const int estimate_time_ms) { - assert(estimate_time_ms > 0); - if (estimate_time_ms <= 0) - return 1; - double multiplier = 1000.0 / (double)estimate_time_ms; // scale by this much - - const int64 start_ticks = CycleClock::Now(); - SleepForMilliseconds(estimate_time_ms); - const int64 guess = int64(multiplier * (CycleClock::Now() - start_ticks)); - return guess; -} - -// ReadIntFromFile is only called on linux and cygwin platforms. -#if defined(__linux__) || defined(__CYGWIN__) || defined(__CYGWIN32__) -// 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. -static bool ReadIntFromFile(const char *file, int *value) { - bool ret = false; - int fd = open(file, O_RDONLY); - if (fd != -1) { - char line[1024]; - char* err; - memset(line, '\0', sizeof(line)); - read(fd, line, sizeof(line) - 1); - const int temp_value = strtol(line, &err, 10); - if (line[0] != '\0' && (*err == '\n' || *err == '\0')) { - *value = temp_value; - ret = true; - } - close(fd); - } - return ret; -} -#endif - -// WARNING: logging calls back to InitializeSystemInfo() so it must -// not invoke any logging code. Also, InitializeSystemInfo() can be -// called before main() -- in fact it *must* be since already_called -// isn't protected -- before malloc hooks are properly set up, so -// we make an effort not to call any routines which might allocate -// memory. - -static void InitializeSystemInfo() { - static bool already_called = false; // safe if we run before threads - if (already_called) return; - already_called = true; - - bool saw_mhz = false; - - if (RunningOnValgrind()) { - // Valgrind may slow the progress of time artificially (--scale-time=N - // option). We thus can't rely on CPU Mhz info stored in /sys or /proc - // files. Thus, actually measure the cps. - cpuinfo_cycles_per_second = EstimateCyclesPerSecond(100); - saw_mhz = true; - } - -#if defined(__linux__) || defined(__CYGWIN__) || defined(__CYGWIN32__) - char line[1024]; - char* err; - int freq; - - // 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 machine, 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 = EstimateCyclesPerSecond(1000); - } - return; // TODO: use generic tester instead? - } - - double bogo_clock = 1.0; - bool saw_bogo = false; - int num_cpus = 0; - line[0] = line[1] = '\0'; - int 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 int 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 == NULL) { - const int linelen = strlen(line); - const int bytes_to_read = sizeof(line)-1 - linelen; - assert(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 != NULL) - *newline = '\0'; - -#if defined(__powerpc__) || defined(__ppc__) - // PowerPC cpus report the frequency in "clock" line - if (strncasecmp(line, "clock", sizeof("clock")-1) == 0) { - const char* freqstr = strchr(line, ':'); - if (freqstr) { - // PowerPC frequencies are only reported as MHz (check 'show_cpuinfo' - // function at arch/powerpc/kernel/setup-common.c) - char *endp = strstr(line, "MHz"); - if (endp) { - *endp = 0; - 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 - // 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 && strncasecmp(line, "cpu MHz", sizeof("cpu MHz")-1) == 0) { - 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 (strncasecmp(line, "bogomips", sizeof("bogomips")-1) == 0) { - 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; - } -#endif - } else if (strncasecmp(line, "processor", sizeof("processor")-1) == 0) { - num_cpus++; // count up every time we see an "processor :" entry - } - } 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 = EstimateCyclesPerSecond(1000); - } - } - if (cpuinfo_cycles_per_second == 0.0) { - cpuinfo_cycles_per_second = 1.0; // maybe unnecessary, but safe - } - if (num_cpus > 0) { - cpuinfo_num_cpus = num_cpus; - } - -#elif defined __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, NULL, 0) != 0 ) { - fprintf(stderr, "Unable to determine clock rate from sysctl: %s: %s\n", - sysctl_path, strerror(errno)); - cpuinfo_cycles_per_second = EstimateCyclesPerSecond(1000); - } else { - cpuinfo_cycles_per_second = hz; - } - // TODO(csilvers): also figure out cpuinfo_num_cpus - -#elif defined(PLATFORM_WINDOWS) -# pragma comment(lib, "shlwapi.lib") // for SHGetValue() - // In NT, read MHz from the registry. If we fail to do so or we're in win9x - // then make a crude estimate. - OSVERSIONINFO os; - os.dwOSVersionInfoSize = sizeof(os); - DWORD data, data_size = sizeof(data); - if (GetVersionEx(&os) && - os.dwPlatformId == VER_PLATFORM_WIN32_NT && - SUCCEEDED(SHGetValueA(HKEY_LOCAL_MACHINE, - "HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0", - "~MHz", NULL, &data, &data_size))) - cpuinfo_cycles_per_second = (int64)data * (int64)(1000 * 1000); // was mhz - else - cpuinfo_cycles_per_second = EstimateCyclesPerSecond(500); // TODO <500? - +int GetSystemCPUsCount() +{ +#if defined(PLATFORM_WINDOWS) // Get the number of processors. SYSTEM_INFO info; GetSystemInfo(&info); - cpuinfo_num_cpus = info.dwNumberOfProcessors; - -#elif defined(__MACH__) && defined(__APPLE__) - // returning "mach time units" per second. the current number of elapsed - // mach time units can be found by calling uint64 mach_absolute_time(); - // while not as precise as actual CPU cycles, it is accurate in the face - // of CPU frequency scaling and multi-cpu/core machines. - // Our mac users have these types of machines, and accuracy - // (i.e. correctness) trumps precision. - // See cycleclock.h: CycleClock::Now(), which returns number of mach time - // units on Mac OS X. - mach_timebase_info_data_t timebase_info; - mach_timebase_info(&timebase_info); - double mach_time_units_per_nanosecond = - static_cast<double>(timebase_info.denom) / - static_cast<double>(timebase_info.numer); - cpuinfo_cycles_per_second = mach_time_units_per_nanosecond * 1e9; - - int num_cpus = 0; - size_t size = sizeof(num_cpus); - int numcpus_name[] = { CTL_HW, HW_NCPU }; - if (::sysctl(numcpus_name, arraysize(numcpus_name), &num_cpus, &size, 0, 0) - == 0 - && (size == sizeof(num_cpus))) - cpuinfo_num_cpus = num_cpus; - + return info.dwNumberOfProcessors; #else - // Generic cycles per second counter - cpuinfo_cycles_per_second = EstimateCyclesPerSecond(1000); -#endif -} - -double CyclesPerSecond(void) { - InitializeSystemInfo(); - return cpuinfo_cycles_per_second; -} - -int NumCPUs(void) { - InitializeSystemInfo(); - return cpuinfo_num_cpus; -} - -// ---------------------------------------------------------------------- -// HasPosixThreads() -// Return true if we're running POSIX (e.g., NPTL on Linux) -// threads, as opposed to a non-POSIX thread library. The thing -// that we care about is whether a thread's pid is the same as -// the thread that spawned it. If so, this function returns -// true. -// ---------------------------------------------------------------------- -bool HasPosixThreads() { -#if defined(__linux__) -#ifndef _CS_GNU_LIBPTHREAD_VERSION -#define _CS_GNU_LIBPTHREAD_VERSION 3 + long rv = sysconf(_SC_NPROCESSORS_ONLN); + if (rv < 0) { + return 1; + } + return static_cast<int>(rv); #endif - char buf[32]; - // We assume that, if confstr() doesn't know about this name, then - // the same glibc is providing LinuxThreads. - if (confstr(_CS_GNU_LIBPTHREAD_VERSION, buf, sizeof(buf)) == 0) - return false; - return strncmp(buf, "NPTL", 4) == 0; -#elif defined(PLATFORM_WINDOWS) || defined(__CYGWIN__) || defined(__CYGWIN32__) - return false; -#else // other OS - return true; // Assume that everything else has Posix -#endif // else OS_LINUX } // ---------------------------------------------------------------------- diff --git a/src/base/sysinfo.h b/src/base/sysinfo.h index cc5cb74..e30b0d4 100644 --- a/src/base/sysinfo.h +++ b/src/base/sysinfo.h @@ -70,14 +70,10 @@ extern const char* GetenvBeforeMain(const char* name); // reasons, as documented in sysinfo.cc. path must have space PATH_MAX. extern bool GetUniquePathFromEnv(const char* env_name, char* path); -extern int NumCPUs(); +extern int GetSystemCPUsCount(); void SleepForMilliseconds(int milliseconds); -// processor cycles per second of each processor. Thread-safe. -extern double CyclesPerSecond(void); - - // Return true if we're running POSIX (e.g., NPTL on Linux) threads, // as opposed to a non-POSIX thread library. The thing that we care // about is whether a thread's pid is the same as the thread that |