gcc/libgo/runtime/yield.c

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "config.h"
#include <stddef.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sched.h>
#include <unistd.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#if defined (__i386__) || defined (__x86_64__)
#include <xmmintrin.h>
#endif
#include "runtime.h"
/* Spin wait. */
void
runtime_procyield (uint32 cnt)
{
volatile uint32 i;
for (i = 0; i < cnt; ++i)
{
#if defined (__i386__) || defined (__x86_64__)
_mm_pause ();
#endif
}
}
/* Ask the OS to reschedule this thread. */
void
runtime_osyield (void)
{
sched_yield ();
}
/* Sleep for some number of microseconds. */
void
runtime_usleep (uint32 us)
{
struct timeval tv;
tv.tv_sec = us / 1000000;
tv.tv_usec = us % 1000000;
select (0, NULL, NULL, NULL, &tv);
}