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-rw-r--r--src/common/x64/cpu_wait.cpp52
1 files changed, 38 insertions, 14 deletions
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();
}