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/*-
* BSD LICENSE
*
* Copyright(c) 2015 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Intel Corporation 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
* OWNER 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.
*/
#define NSEC_PER_SEC 1000000000L
/**
* Structure to hold the parameters of a running cycle counter to assist
* in converting cycles to nanoseconds.
*/
struct rte_timecounter {
/** Last cycle counter value read. */
uint64_t cycle_last;
/** Nanoseconds count. */
uint64_t nsec;
/** Bitmask separating nanosecond and sub-nanoseconds. */
uint64_t nsec_mask;
/** Sub-nanoseconds count. */
uint64_t nsec_frac;
/** Bitmask for two's complement substraction of non-64 bit counters. */
uint64_t cc_mask;
/** Cycle to nanosecond divisor (power of two). */
uint32_t cc_shift;
};
/**
* Converts cyclecounter cycles to nanoseconds.
*/
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;
}
/**
* Update the internal nanosecond count in the structure.
*/
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;
}
/**
* Convert from timespec structure into nanosecond units.
*/
static inline uint64_t
rte_timespec_to_ns(const struct timespec *ts)
{
return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}
/**
* Convert from nanosecond units into timespec structure.
*/
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;
}
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