root/sys/sys/microtime_pcpu.h
/*
 * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Sepherosa Ziehau <sepherosa@gmail.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of The DragonFly Project 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
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _SYS_MICROTIME_PCPU_H_
#define _SYS_MICROTIME_PCPU_H_

#ifndef _SYS_PARAM_H_
#include <sys/param.h>
#endif

#ifndef _SYS_TIME_H_
#include <sys/time.h>
#endif

#include <machine/clock.h>
#include <machine/cpufunc.h>

/*
 * This 'time' only guarantees monotonicly increment on the same CPU
 */

union microtime_pcpu {
        struct timeval  tv;
        uint64_t        tsc;
};

static __inline void
microtime_pcpu_get(union microtime_pcpu *t)
{
        if (tsc_invariant)
                t->tsc = rdtsc();
        else
                microuptime(&t->tv);
}

static __inline int
microtime_pcpu_diff(const union microtime_pcpu *s,
                    const union microtime_pcpu *e)
{
        if (tsc_invariant) {
                return (((e->tsc - s->tsc) * 1000000) /
                        (tsc_sclock_t)tsc_frequency);
        } else {
                return ((e->tv.tv_usec - s->tv.tv_usec) +
                        (e->tv.tv_sec - s->tv.tv_sec) * 1000000);
        }
}

#endif  /* !_SYS_MICROTIME_PCPU_H_ */