1 //===-- Utilities for suspending threads ----------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 10 #define LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 11 12 #include "src/__support/macros/attributes.h" 13 14 namespace LIBC_NAMESPACE { 15 16 /// Suspend the thread briefly to assist the thread scheduler during busy loops. sleep_briefly()17LIBC_INLINE void sleep_briefly() { 18 #if defined(LIBC_TARGET_ARCH_IS_NVPTX) 19 if (__nvvm_reflect("__CUDA_ARCH") >= 700) 20 LIBC_INLINE_ASM("nanosleep.u32 64;" ::: "memory"); 21 #elif defined(LIBC_TARGET_ARCH_IS_AMDGPU) 22 __builtin_amdgcn_s_sleep(2); 23 #elif defined(LIBC_TARGET_ARCH_IS_X86) 24 __builtin_ia32_pause(); 25 #elif defined(LIBC_TARGET_ARCH_IS_AARCH64) 26 __builtin_arm_isb(0xf); 27 #else 28 // Simply do nothing if sleeping isn't supported on this platform. 29 #endif 30 } 31 32 } // namespace LIBC_NAMESPACE 33 34 #endif // LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 35