• Pieter Hintjens's avatar
    Removed corporate advertisements from source file headers · f0f16505
    Pieter Hintjens authored
    Copyrights had become ads for Sustrik's corporate sponsors, going against the original
    agreement to share copyrights with the community (that agreement was: one line stating
    iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads
    is also unfair to the many individual authors. I've removed ALL corporate title from
    the source files so the copyright statements can now be centralized in AUTHORS and
    source files can be properly updated on an annual basis.
    f0f16505
clock.cpp 4.04 KB
/*
    Copyright (c) 2007-2013 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 _WIN32_WCE
#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 = ticksPerSecond.QuadPart / 1000000.0;     
    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
}