Line data    Source code

       1             : /*
       2             :  *
       3             :  * Copyright 2015, Google Inc.
       4             :  * All rights reserved.
       5             :  *
       6             :  * Redistribution and use in source and binary forms, with or without
       7             :  * modification, are permitted provided that the following conditions are
       8             :  * met:
       9             :  *
      10             :  *     * Redistributions of source code must retain the above copyright
      11             :  * notice, this list of conditions and the following disclaimer.
      12             :  *     * Redistributions in binary form must reproduce the above
      13             :  * copyright notice, this list of conditions and the following disclaimer
      14             :  * in the documentation and/or other materials provided with the
      15             :  * distribution.
      16             :  *     * Neither the name of Google Inc. nor the names of its
      17             :  * contributors may be used to endorse or promote products derived from
      18             :  * this software without specific prior written permission.
      19             :  *
      20             :  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      21             :  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      22             :  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      23             :  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      24             :  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      25             :  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      26             :  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      27             :  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      28             :  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      29             :  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      30             :  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      31             :  *
      32             :  */
      33             : 
      34             : #include <grpc/support/log.h>
      35             : #include <grpc/support/time.h>
      36             : #include <stdio.h>
      37             : 
      38             : #ifdef GRPC_TIMERS_RDTSC
      39             : #if defined(__i386__)
      40             : static void gpr_get_cycle_counter(long long int *clk) {
      41             :   long long int ret;
      42             :   __asm__ volatile("rdtsc" : "=A"(ret));
      43             :   *clk = ret;
      44             : }
      45             : 
      46             : // ----------------------------------------------------------------
      47             : #elif defined(__x86_64__) || defined(__amd64__)
      48             : static void gpr_get_cycle_counter(long long int *clk) {
      49             :   unsigned long long low, high;
      50             :   __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
      51             :   *clk = (long long)(high << 32) | (long long)low;
      52             : }
      53             : #endif
      54             : 
      55             : static double cycles_per_second = 0;
      56             : static long long int start_cycle;
      57             : void gpr_precise_clock_init(void) {
      58             :   time_t start;
      59             :   long long end_cycle;
      60             :   gpr_log(GPR_DEBUG, "Calibrating timers");
      61             :   start = time(NULL);
      62             :   while (time(NULL) == start)
      63             :     ;
      64             :   gpr_get_cycle_counter(&start_cycle);
      65             :   while (time(NULL) <= start + 10)
      66             :     ;
      67             :   gpr_get_cycle_counter(&end_cycle);
      68             :   cycles_per_second = (double)(end_cycle - start_cycle) / 10.0;
      69             :   gpr_log(GPR_DEBUG, "... cycles_per_second = %f\n", cycles_per_second);
      70             : }
      71             : 
      72             : void gpr_precise_clock_now(gpr_timespec *clk) {
      73             :   long long int counter;
      74             :   double secs;
      75             :   gpr_get_cycle_counter(&counter);
      76             :   secs = (double)(counter - start_cycle) / cycles_per_second;
      77             :   clk->clock_type = GPR_CLOCK_PRECISE;
      78             :   clk->tv_sec = (time_t)secs;
      79             :   clk->tv_nsec = (int)(1e9 * (secs - (double)clk->tv_sec));
      80             : }
      81             : 
      82             : #else  /* GRPC_TIMERS_RDTSC */
      83        3452 : void gpr_precise_clock_init(void) {}
      84             : 
      85           0 : void gpr_precise_clock_now(gpr_timespec *clk) {
      86           0 :   *clk = gpr_now(GPR_CLOCK_REALTIME);
      87           0 :   clk->clock_type = GPR_CLOCK_PRECISE;
      88           0 : }
      89             : #endif /* GRPC_TIMERS_RDTSC */