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/*
Copyright (c) 2007-2011 iMatix Corporation
Copyright (c) 2007-2011 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
#include <intrin.h>
#endif
#if !defined ZMQ_HAVE_WINDOWS
#include <sys/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);
#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
}
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