diff options
| -rw-r--r-- | src/common/x64/cpu_wait.cpp | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp index c53dd4945..11b9c4d83 100644 --- a/src/common/x64/cpu_wait.cpp +++ b/src/common/x64/cpu_wait.cpp @@ -13,24 +13,30 @@ namespace Common::X64 { +namespace { + +// 100,000 cycles is a reasonable amount of time to wait to save on CPU resources. +// For reference: +// At 1 GHz, 100K cycles is 100us +// At 2 GHz, 100K cycles is 50us +// At 4 GHz, 100K cycles is 25us +constexpr auto PauseCycles = 100'000U; + +} // Anonymous namespace + #ifdef _MSC_VER __forceinline static void TPAUSE() { - // 100,000 cycles is a reasonable amount of time to wait to save on CPU resources. - // For reference: - // At 1 GHz, 100K cycles is 100us - // At 2 GHz, 100K cycles is 50us - // At 4 GHz, 100K cycles is 25us - static constexpr auto PauseCycles = 100'000; _tpause(0, FencedRDTSC() + PauseCycles); } + +__forceinline static void MWAITX() { + // monitor_var should be aligned to a cache line. + alignas(64) u64 monitor_var{}; + _mm_monitorx(&monitor_var, 0, 0); + _mm_mwaitx(/* extensions*/ 2, /* hints */ 0, /* cycles */ PauseCycles); +} #else static void TPAUSE() { - // 100,000 cycles is a reasonable amount of time to wait to save on CPU resources. - // For reference: - // At 1 GHz, 100K cycles is 100us - // At 2 GHz, 100K cycles is 50us - // At 4 GHz, 100K cycles is 25us - static constexpr auto PauseCycles = 100'000; const auto tsc = FencedRDTSC() + PauseCycles; const auto eax = static_cast<u32>(tsc & 0xFFFFFFFF); const auto edx = static_cast<u32>(tsc >> 32); @@ -40,9 +46,12 @@ static void TPAUSE() { void MicroSleep() { static const bool has_waitpkg = GetCPUCaps().waitpkg; + static const bool has_monitorx = GetCPUCaps().monitorx; if (has_waitpkg) { TPAUSE(); + } else if (has_monitorx) { + MWAITX(); } else { std::this_thread::yield(); } |