diff options
| -rw-r--r-- | src/common/telemetry.cpp | 1 | ||||
| -rw-r--r-- | src/common/x64/cpu_detect.cpp | 1 | ||||
| -rw-r--r-- | src/common/x64/cpu_detect.h | 1 | ||||
| -rw-r--r-- | src/common/x64/cpu_wait.cpp | 52 |
4 files changed, 41 insertions, 14 deletions
diff --git a/src/common/telemetry.cpp b/src/common/telemetry.cpp index 91352912d..929ed67e4 100644 --- a/src/common/telemetry.cpp +++ b/src/common/telemetry.cpp @@ -93,6 +93,7 @@ void AppendCPUInfo(FieldCollection& fc) { add_field("CPU_Extension_x64_GFNI", caps.gfni); add_field("CPU_Extension_x64_INVARIANT_TSC", caps.invariant_tsc); add_field("CPU_Extension_x64_LZCNT", caps.lzcnt); + add_field("CPU_Extension_x64_MONITORX", caps.monitorx); add_field("CPU_Extension_x64_MOVBE", caps.movbe); add_field("CPU_Extension_x64_PCLMULQDQ", caps.pclmulqdq); add_field("CPU_Extension_x64_POPCNT", caps.popcnt); diff --git a/src/common/x64/cpu_detect.cpp b/src/common/x64/cpu_detect.cpp index c998b1197..780120a5b 100644 --- a/src/common/x64/cpu_detect.cpp +++ b/src/common/x64/cpu_detect.cpp @@ -168,6 +168,7 @@ static CPUCaps Detect() { __cpuid(cpu_id, 0x80000001); caps.lzcnt = Common::Bit<5>(cpu_id[2]); caps.fma4 = Common::Bit<16>(cpu_id[2]); + caps.monitorx = Common::Bit<29>(cpu_id[2]); } if (max_ex_fn >= 0x80000007) { diff --git a/src/common/x64/cpu_detect.h b/src/common/x64/cpu_detect.h index 8253944d6..756459417 100644 --- a/src/common/x64/cpu_detect.h +++ b/src/common/x64/cpu_detect.h @@ -63,6 +63,7 @@ struct CPUCaps { bool gfni : 1; bool invariant_tsc : 1; bool lzcnt : 1; + bool monitorx : 1; bool movbe : 1; bool pclmulqdq : 1; bool popcnt : 1; diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp index c53dd4945..41d385f59 100644 --- a/src/common/x64/cpu_wait.cpp +++ b/src/common/x64/cpu_wait.cpp @@ -13,36 +13,60 @@ 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); + static constexpr auto RequestC02State = 0U; + _tpause(RequestC02State, FencedRDTSC() + PauseCycles); +} + +__forceinline static void MWAITX() { + static constexpr auto EnableWaitTimeFlag = 1U << 1; + static constexpr auto RequestC1State = 0U; + + // monitor_var should be aligned to a cache line. + alignas(64) u64 monitor_var{}; + _mm_monitorx(&monitor_var, 0, 0); + _mm_mwaitx(EnableWaitTimeFlag, RequestC1State, 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; + static constexpr auto RequestC02State = 0U; const auto tsc = FencedRDTSC() + PauseCycles; const auto eax = static_cast<u32>(tsc & 0xFFFFFFFF); const auto edx = static_cast<u32>(tsc >> 32); - asm volatile("tpause %0" : : "r"(0), "d"(edx), "a"(eax)); + asm volatile("tpause %0" : : "r"(RequestC02State), "d"(edx), "a"(eax)); +} + +static void MWAITX() { + static constexpr auto EnableWaitTimeFlag = 1U << 1; + static constexpr auto RequestC1State = 0U; + + // monitor_var should be aligned to a cache line. + alignas(64) u64 monitor_var{}; + asm volatile("monitorx" : : "a"(&monitor_var), "c"(0), "d"(0)); + asm volatile("mwaitx" : : "a"(RequestC1State), "b"(PauseCycles), "c"(EnableWaitTimeFlag)); } #endif 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(); } |