rte_time.h

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2015 Intel Corporation
 */

#ifndef _RTE_TIME_H_
#define _RTE_TIME_H_

#include <stdint.h>
#include <time.h>

#define NSEC_PER_SEC             1000000000L

struct rte_timecounter {
    uint64_t cycle_last;
    uint64_t nsec;
    uint64_t nsec_mask;
    uint64_t nsec_frac;
    uint64_t cc_mask;
    uint32_t cc_shift;
};

static inline uint64_t
rte_cyclecounter_cycles_to_ns(struct rte_timecounter *tc, uint64_t cycles)
{
    uint64_t ns;

    /* Add fractional nanoseconds. */
    ns = cycles + tc->nsec_frac;
    tc->nsec_frac = ns & tc->nsec_mask;

    /* Shift to get only nanoseconds. */
    return ns >> tc->cc_shift;
}

static inline uint64_t
rte_timecounter_update(struct rte_timecounter *tc, uint64_t cycle_now)
{
    uint64_t cycle_delta, ns_offset;

    /* Calculate the delta since the last call. */
    if (tc->cycle_last <= cycle_now)
        cycle_delta = (cycle_now - tc->cycle_last) & tc->cc_mask;
    else
        /* Handle cycle counts that have wrapped around . */
        cycle_delta = (~(tc->cycle_last - cycle_now) & tc->cc_mask) + 1;

    /* Convert to nanoseconds. */
    ns_offset = rte_cyclecounter_cycles_to_ns(tc, cycle_delta);

    /* Store current cycle counter for next call. */
    tc->cycle_last = cycle_now;

    /* Update the nanosecond count. */
    tc->nsec += ns_offset;

    return tc->nsec;
}

static inline uint64_t
rte_timespec_to_ns(const struct timespec *ts)
{
    return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}

static inline struct timespec
rte_ns_to_timespec(uint64_t nsec)
{
    struct timespec ts = {0, 0};

    if (nsec == 0)
        return ts;

    ts.tv_sec = nsec / NSEC_PER_SEC;
    ts.tv_nsec = nsec % NSEC_PER_SEC;

    return ts;
}

#endif /* _RTE_TIME_H_ */