diff options
Diffstat (limited to 'src/core/core_timing.cpp')
| -rw-r--r-- | src/core/core_timing.cpp | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp index 6f45a270db..6be73e84d8 100644 --- a/src/core/core_timing.cpp +++ b/src/core/core_timing.cpp @@ -13,6 +13,11 @@ #include "common/windows/timer_resolution.h" #endif +#if defined(_WIN32) && defined(ARCHITECTURE_x86_64) && defined(__MINGW64__) +#include "common/x64/cpu_detect.h" +#include "common/x64/rdtsc.h" +#endif + #include "common/settings.h" #include "core/core_timing.h" #include "core/hardware_properties.h" @@ -282,8 +287,45 @@ void CoreTiming::ThreadLoop() { const auto next_time = Advance(); if (next_time) { // There are more events left in the queue, wait until the next event. - auto wait_time = *next_time - GetGlobalTimeNs().count(); - event.WaitFor(std::chrono::nanoseconds(wait_time)); + if (auto wait_time = *next_time - GetGlobalTimeNs().count(); wait_time > 0) { +#if defined(_WIN32) && defined(ARCHITECTURE_x86_64) && defined(__MINGW64__) + while (!paused && !event.IsSet() && wait_time > 0) { + wait_time = *next_time - GetGlobalTimeNs().count(); + if (wait_time >= timer_resolution_ns) { + Common::Windows::SleepForOneTick(); + } else { + // 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; + auto const& caps = Common::GetCPUCaps(); + if (caps.waitpkg) { + static constexpr auto RequestC02State = 0U; + const auto tsc = Common::X64::FencedRDTSC() + PauseCycles; + const auto eax = u32(tsc & 0xFFFFFFFF); + const auto edx = u32(tsc >> 32); + asm volatile("tpause %0" : : "r"(RequestC02State), "d"(edx), "a"(eax)); + } else if (caps.monitorx) { + 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)); + } else { + std::this_thread::yield(); + } + } + } + if (event.IsSet()) { + event.Reset(); + } +#else + event.WaitFor(std::chrono::nanoseconds(wait_time)); +#endif + } } else { // Queue is empty, wait until another event is scheduled and signals us to // continue. |