| // -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- |
| // Copyright (c) 2004, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| // ---------------------------------------------------------------------- |
| // CycleClock |
| // A CycleClock tells you the current time in Cycles. The "time" |
| // is actually time since power-on. This is like time() but doesn't |
| // involve a system call and is much more precise. |
| // |
| // NOTE: Not all cpu/platform/kernel combinations guarantee that this |
| // clock increments at a constant rate or is synchronized across all logical |
| // cpus in a system. |
| // |
| // Also, in some out of order CPU implementations, the CycleClock is not |
| // serializing. So if you're trying to count at cycles granularity, your |
| // data might be inaccurate due to out of order instruction execution. |
| // ---------------------------------------------------------------------- |
| |
| #ifndef GOOGLE_BASE_CYCLECLOCK_H_ |
| #define GOOGLE_BASE_CYCLECLOCK_H_ |
| |
| #include "base/basictypes.h" // make sure we get the def for int64 |
| #include "base/arm_instruction_set_select.h" |
| // base/sysinfo.h is really big and we don't want to include it unless |
| // it is necessary. |
| #if defined(__arm__) || defined(__mips__) || defined(__aarch64__) |
| # include "base/sysinfo.h" |
| #endif |
| #if defined(__MACH__) && defined(__APPLE__) |
| # include <mach/mach_time.h> |
| #endif |
| // For MSVC, we want to use '_asm rdtsc' when possible (since it works |
| // with even ancient MSVC compilers), and when not possible the |
| // __rdtsc intrinsic, declared in <intrin.h>. Unfortunately, in some |
| // environments, <windows.h> and <intrin.h> have conflicting |
| // declarations of some other intrinsics, breaking compilation. |
| // Therefore, we simply declare __rdtsc ourselves. See also |
| // http://connect.microsoft.com/VisualStudio/feedback/details/262047 |
| #if defined(_MSC_VER) && !defined(_M_IX86) |
| extern "C" uint64 __rdtsc(); |
| #pragma intrinsic(__rdtsc) |
| #endif |
| #if defined(ARMV3) || defined(__mips__) || defined(__aarch64__) |
| #include <sys/time.h> |
| #endif |
| |
| // NOTE: only i386 and x86_64 have been well tested. |
| // PPC, sparc, alpha, and ia64 are based on |
| // http://peter.kuscsik.com/wordpress/?p=14 |
| // with modifications by m3b. See also |
| // https://setisvn.ssl.berkeley.edu/svn/lib/fftw-3.0.1/kernel/cycle.h |
| struct CycleClock { |
| // This should return the number of cycles since power-on. Thread-safe. |
| static inline int64 Now() { |
| #if defined(__MACH__) && defined(__APPLE__) |
| // this goes at the top because we need ALL Macs, regardless of |
| // architecture, to return the number of "mach time units" that |
| // have passed since startup. See sysinfo.cc where |
| // InitializeSystemInfo() sets the supposed cpu clock frequency of |
| // macs to the number of mach time units per second, not actual |
| // CPU clock frequency (which can change in the face of CPU |
| // frequency scaling). Also note that when the Mac sleeps, this |
| // counter pauses; it does not continue counting, nor does it |
| // reset to zero. |
| return mach_absolute_time(); |
| #elif defined(__i386__) |
| int64 ret; |
| __asm__ volatile ("rdtsc" : "=A" (ret) ); |
| return ret; |
| #elif defined(__x86_64__) || defined(__amd64__) |
| uint64 low, high; |
| __asm__ volatile ("rdtsc" : "=a" (low), "=d" (high)); |
| return (high << 32) | low; |
| #elif defined(__powerpc64__) || defined(__ppc64__) |
| uint64 tb; |
| __asm__ volatile (\ |
| "mfspr %0, 268" |
| : "=r" (tb)); |
| return tb; |
| #elif defined(__powerpc__) || defined(__ppc__) |
| // This returns a time-base, which is not always precisely a cycle-count. |
| uint32 tbu, tbl, tmp; |
| __asm__ volatile (\ |
| "0:\n" |
| "mftbu %0\n" |
| "mftbl %1\n" |
| "mftbu %2\n" |
| "cmpw %0, %2\n" |
| "bne- 0b" |
| : "=r" (tbu), "=r" (tbl), "=r" (tmp)); |
| return (((uint64) tbu << 32) | tbl); |
| #elif defined(__sparc__) |
| int64 tick; |
| asm(".byte 0x83, 0x41, 0x00, 0x00"); |
| asm("mov %%g1, %0" : "=r" (tick)); |
| return tick; |
| #elif defined(__ia64__) |
| int64 itc; |
| asm("mov %0 = ar.itc" : "=r" (itc)); |
| return itc; |
| #elif defined(_MSC_VER) && defined(_M_IX86) |
| // Older MSVC compilers (like 7.x) don't seem to support the |
| // __rdtsc intrinsic properly, so I prefer to use _asm instead |
| // when I know it will work. Otherwise, I'll use __rdtsc and hope |
| // the code is being compiled with a non-ancient compiler. |
| _asm rdtsc |
| #elif defined(_MSC_VER) |
| return __rdtsc(); |
| #elif defined(ARMV3) || defined(__aarch64__) |
| #if defined(ARMV7) // V7 is the earliest arch that has a standard cyclecount |
| uint32 pmccntr; |
| uint32 pmuseren; |
| uint32 pmcntenset; |
| // Read the user mode perf monitor counter access permissions. |
| asm volatile ("mrc p15, 0, %0, c9, c14, 0" : "=r" (pmuseren)); |
| if (pmuseren & 1) { // Allows reading perfmon counters for user mode code. |
| asm volatile ("mrc p15, 0, %0, c9, c12, 1" : "=r" (pmcntenset)); |
| if (pmcntenset & 0x80000000ul) { // Is it counting? |
| asm volatile ("mrc p15, 0, %0, c9, c13, 0" : "=r" (pmccntr)); |
| // The counter is set up to count every 64th cycle |
| return static_cast<int64>(pmccntr) * 64; // Should optimize to << 6 |
| } |
| } |
| #endif |
| struct timeval tv; |
| gettimeofday(&tv, NULL); |
| return static_cast<int64>((tv.tv_sec + tv.tv_usec * 0.000001) |
| * CyclesPerSecond()); |
| #elif defined(__mips__) |
| // mips apparently only allows rdtsc for superusers, so we fall |
| // back to gettimeofday. It's possible clock_gettime would be better. |
| struct timeval tv; |
| gettimeofday(&tv, NULL); |
| return static_cast<int64>((tv.tv_sec + tv.tv_usec * 0.000001) |
| * CyclesPerSecond()); |
| #else |
| // The soft failover to a generic implementation is automatic only for ARM. |
| // For other platforms the developer is expected to make an attempt to create |
| // a fast implementation and use generic version if nothing better is available. |
| #error You need to define CycleTimer for your O/S and CPU |
| #endif |
| } |
| }; |
| |
| |
| #endif // GOOGLE_BASE_CYCLECLOCK_H_ |
