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/*
*
* Copyright 2015-2016, Google Inc.
* 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 Google Inc. 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.
*
*/
#include <grpc/support/log.h>
#include <grpc/support/time.h>
#include <stdio.h>
#ifdef GRPC_TIMERS_RDTSC
#if defined(__i386__)
static void gpr_get_cycle_counter(long long int *clk) {
long long int ret;
__asm__ volatile("rdtsc" : "=A"(ret));
*clk = ret;
}
// ----------------------------------------------------------------
#elif defined(__x86_64__) || defined(__amd64__)
static void gpr_get_cycle_counter(long long int *clk) {
unsigned long long low, high;
__asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
*clk = (long long)(high << 32) | (long long)low;
}
#endif
static double cycles_per_second = 0;
static long long int start_cycle;
void gpr_precise_clock_init(void) {
time_t start;
long long end_cycle;
gpr_log(GPR_DEBUG, "Calibrating timers");
start = time(NULL);
while (time(NULL) == start)
;
gpr_get_cycle_counter(&start_cycle);
while (time(NULL) <= start + 10)
;
gpr_get_cycle_counter(&end_cycle);
cycles_per_second = (double)(end_cycle - start_cycle) / 10.0;
gpr_log(GPR_DEBUG, "... cycles_per_second = %f\n", cycles_per_second);
}
void gpr_precise_clock_now(gpr_timespec *clk) {
long long int counter;
double secs;
gpr_get_cycle_counter(&counter);
secs = (double)(counter - start_cycle) / cycles_per_second;
clk->clock_type = GPR_CLOCK_PRECISE;
clk->tv_sec = (int64_t)secs;
clk->tv_nsec = (int32_t)(1e9 * (secs - (double)clk->tv_sec));
}
#else /* GRPC_TIMERS_RDTSC */
void gpr_precise_clock_init(void) {}
void gpr_precise_clock_now(gpr_timespec *clk) {
*clk = gpr_now(GPR_CLOCK_REALTIME);
clk->clock_type = GPR_CLOCK_PRECISE;
}
#endif /* GRPC_TIMERS_RDTSC */
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