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Diffstat (limited to 'src/clock.cpp')
| -rw-r--r-- | src/clock.cpp | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/src/clock.cpp b/src/clock.cpp new file mode 100644 index 0000000..1646397 --- /dev/null +++ b/src/clock.cpp @@ -0,0 +1,147 @@ +/* + Copyright (c) 2010-2011 250bpm s.r.o. + Copyright (c) 2010-2011 Other contributors as noted in the AUTHORS file + + This file is part of 0MQ. + + 0MQ is free software; you can redistribute it and/or modify it under + the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + 0MQ is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "clock.hpp" +#include "platform.hpp" +#include "likely.hpp" +#include "config.hpp" +#include "err.hpp" + +#include <stddef.h> + +#if defined _MSC_VER +#if defined WINCE +#include <cmnintrin.h> +#else +#include <intrin.h> +#endif +#endif + +#if !defined ZMQ_HAVE_WINDOWS +#include <sys/time.h> +#endif + +#if defined HAVE_CLOCK_GETTIME || defined HAVE_GETHRTIME +#include <time.h> +#endif + +zmq::clock_t::clock_t () : + last_tsc (rdtsc ()), + last_time (now_us () / 1000) +{ +} + +zmq::clock_t::~clock_t () +{ +} + +uint64_t zmq::clock_t::now_us () +{ +#if defined ZMQ_HAVE_WINDOWS + + // Get the high resolution counter's accuracy. + LARGE_INTEGER ticksPerSecond; + QueryPerformanceFrequency (&ticksPerSecond); + + // What time is it? + LARGE_INTEGER tick; + QueryPerformanceCounter (&tick); + + // Convert the tick number into the number of seconds + // since the system was started. + double ticks_div = (double) (ticksPerSecond.QuadPart / 1000000); + return (uint64_t) (tick.QuadPart / ticks_div); + +#elif defined HAVE_CLOCK_GETTIME && defined CLOCK_MONOTONIC + + // Use POSIX clock_gettime function to get precise monotonic time. + struct timespec tv; + int rc = clock_gettime (CLOCK_MONOTONIC, &tv); + // Fix case where system has clock_gettime but CLOCK_MONOTONIC is not supported. + // This should be a configuration check, but I looked into it and writing an + // AC_FUNC_CLOCK_MONOTONIC seems beyond my powers. + if( rc != 0) { + // Use POSIX gettimeofday function to get precise time. + struct timeval tv; + int rc = gettimeofday (&tv, NULL); + errno_assert (rc == 0); + return (tv.tv_sec * (uint64_t) 1000000 + tv.tv_usec); + } + return (tv.tv_sec * (uint64_t) 1000000 + tv.tv_nsec / 1000); + +#elif defined HAVE_GETHRTIME + + return (gethrtime () / 1000); + +#else + + // Use POSIX gettimeofday function to get precise time. + struct timeval tv; + int rc = gettimeofday (&tv, NULL); + errno_assert (rc == 0); + return (tv.tv_sec * (uint64_t) 1000000 + tv.tv_usec); + +#endif +} + +uint64_t zmq::clock_t::now_ms () +{ + uint64_t tsc = rdtsc (); + + // If TSC is not supported, get precise time and chop off the microseconds. + if (!tsc) + return now_us () / 1000; + + // If TSC haven't jumped back (in case of migration to a different + // CPU core) and if not too much time elapsed since last measurement, + // we can return cached time value. + if (likely (tsc - last_tsc <= (clock_precision / 2) && tsc >= last_tsc)) + return last_time; + + last_tsc = tsc; + last_time = now_us () / 1000; + return last_time; +} + +uint64_t zmq::clock_t::rdtsc () +{ +#if (defined _MSC_VER && (defined _M_IX86 || defined _M_X64)) + return __rdtsc (); +#elif (defined __GNUC__ && (defined __i386__ || defined __x86_64__)) + uint32_t low, high; + __asm__ volatile ("rdtsc" : "=a" (low), "=d" (high)); + return (uint64_t) high << 32 | low; +#elif (defined __SUNPRO_CC && (__SUNPRO_CC >= 0x5100) && (defined __i386 || \ + defined __amd64 || defined __x86_64)) + union { + uint64_t u64val; + uint32_t u32val [2]; + } tsc; + asm("rdtsc" : "=a" (tsc.u32val [0]), "=d" (tsc.u32val [1])); + return tsc.u64val; +#elif defined(__s390__) + uint64_t tsc; + asm("\tstck\t%0\n" : "=Q" (tsc) : : "cc"); + tsc >>= 12; /* convert to microseconds just to be consistent */ + return(tsc); +#else + return 0; +#endif +} |