1  // Copyright 2011 The Go Authors. All rights reserved.
       2  // Use of this source code is governed by a BSD-style
       3  // license that can be found in the LICENSE file.
       4  
       5  #include "config.h"
       6  
       7  #include <stddef.h>
       8  #include <sys/types.h>
       9  #include <sys/time.h>
      10  #include <sched.h>
      11  #include <unistd.h>
      12  
      13  #ifdef HAVE_SYS_SELECT_H
      14  #include <sys/select.h>
      15  #endif
      16  
      17  #if defined (__i386__) || defined (__x86_64__)
      18  #include <xmmintrin.h>
      19  #endif
      20  
      21  #include "runtime.h"
      22  
      23  /* Spin wait.  */
      24  
      25  void
      26  runtime_procyield (uint32 cnt)
      27  {
      28    volatile uint32 i;
      29  
      30    for (i = 0; i < cnt; ++i)
      31      {
      32  #if defined (__i386__) || defined (__x86_64__)
      33        _mm_pause ();
      34  #endif
      35      }
      36  }
      37  
      38  /* Ask the OS to reschedule this thread.  */
      39  
      40  void runtime_osyield(void)
      41    __attribute__ ((no_split_stack));
      42  
      43  void
      44  runtime_osyield (void)
      45  {
      46    sched_yield ();
      47  }
      48  
      49  /* Sleep for some number of microseconds.  */
      50  
      51  void
      52  runtime_usleep (uint32 us)
      53  {
      54    struct timeval tv;
      55  
      56    tv.tv_sec = us / 1000000;
      57    tv.tv_usec = us % 1000000;
      58    select (0, NULL, NULL, NULL, &tv);
      59  }