rte_time.h

/*-
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 *   Copyright(c) 2015 Intel Corporation. All rights reserved.
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#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;
}