1*bb722a7dSDimitry Andric //===-- Utilities for suspending threads ----------------------------------===// 2*bb722a7dSDimitry Andric // 3*bb722a7dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*bb722a7dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*bb722a7dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*bb722a7dSDimitry Andric // 7*bb722a7dSDimitry Andric //===----------------------------------------------------------------------===// 8*bb722a7dSDimitry Andric 9*bb722a7dSDimitry Andric #ifndef LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 10*bb722a7dSDimitry Andric #define LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 11*bb722a7dSDimitry Andric 12*bb722a7dSDimitry Andric #include "src/__support/macros/attributes.h" 13*bb722a7dSDimitry Andric #include "src/__support/macros/config.h" 14*bb722a7dSDimitry Andric 15*bb722a7dSDimitry Andric namespace LIBC_NAMESPACE_DECL { 16*bb722a7dSDimitry Andric 17*bb722a7dSDimitry Andric /// Suspend the thread briefly to assist the thread scheduler during busy loops. sleep_briefly()18*bb722a7dSDimitry AndricLIBC_INLINE void sleep_briefly() { 19*bb722a7dSDimitry Andric #if defined(LIBC_TARGET_ARCH_IS_NVPTX) 20*bb722a7dSDimitry Andric if (__nvvm_reflect("__CUDA_ARCH") >= 700) 21*bb722a7dSDimitry Andric LIBC_INLINE_ASM("nanosleep.u32 64;" ::: "memory"); 22*bb722a7dSDimitry Andric #elif defined(LIBC_TARGET_ARCH_IS_AMDGPU) 23*bb722a7dSDimitry Andric __builtin_amdgcn_s_sleep(2); 24*bb722a7dSDimitry Andric #elif defined(LIBC_TARGET_ARCH_IS_X86) 25*bb722a7dSDimitry Andric __builtin_ia32_pause(); 26*bb722a7dSDimitry Andric #elif defined(LIBC_TARGET_ARCH_IS_AARCH64) && __has_builtin(__builtin_arm_isb) 27*bb722a7dSDimitry Andric __builtin_arm_isb(0xf); 28*bb722a7dSDimitry Andric #elif defined(LIBC_TARGET_ARCH_IS_AARCH64) 29*bb722a7dSDimitry Andric asm volatile("isb\n" ::: "memory"); 30*bb722a7dSDimitry Andric #else 31*bb722a7dSDimitry Andric // Simply do nothing if sleeping isn't supported on this platform. 32*bb722a7dSDimitry Andric #endif 33*bb722a7dSDimitry Andric } 34*bb722a7dSDimitry Andric 35*bb722a7dSDimitry Andric } // namespace LIBC_NAMESPACE_DECL 36*bb722a7dSDimitry Andric 37*bb722a7dSDimitry Andric #endif // LLVM_LIBC_SRC___SUPPORT_THREADS_SLEEP_H 38