From d2cfe25b07906f36c688ccacde30e3dc50123e8f Mon Sep 17 00:00:00 2001 From: Morph <39850852+Morph1984@users.noreply.github.com> Date: Tue, 21 Mar 2023 21:13:03 -0400 Subject: x64: cpu_detect: Add detection of waitpkg instructions waitpkg introduces 3 instructions, UMONITOR, UMWAIT and TPAUSE. --- src/common/x64/cpu_detect.cpp | 1 + src/common/x64/cpu_detect.h | 1 + 2 files changed, 2 insertions(+) (limited to 'src/common/x64') diff --git a/src/common/x64/cpu_detect.cpp b/src/common/x64/cpu_detect.cpp index e54383a4a..72ed6e96c 100644 --- a/src/common/x64/cpu_detect.cpp +++ b/src/common/x64/cpu_detect.cpp @@ -144,6 +144,7 @@ static CPUCaps Detect() { caps.bmi2 = Common::Bit<8>(cpu_id[1]); caps.sha = Common::Bit<29>(cpu_id[1]); + caps.waitpkg = Common::Bit<5>(cpu_id[2]); caps.gfni = Common::Bit<8>(cpu_id[2]); __cpuidex(cpu_id, 0x00000007, 0x00000001); diff --git a/src/common/x64/cpu_detect.h b/src/common/x64/cpu_detect.h index ca8db19d6..8253944d6 100644 --- a/src/common/x64/cpu_detect.h +++ b/src/common/x64/cpu_detect.h @@ -67,6 +67,7 @@ struct CPUCaps { bool pclmulqdq : 1; bool popcnt : 1; bool sha : 1; + bool waitpkg : 1; }; /** -- cgit v1.2.3 From 27c33ab73fd03d659654c49967a081214daf6ac2 Mon Sep 17 00:00:00 2001 From: Morph <39850852+Morph1984@users.noreply.github.com> Date: Tue, 21 Mar 2023 21:28:38 -0400 Subject: x64: Add MicroSleep MicroSleep allows the processor to pause for a "short" amount of time (in the microsecond range). This is useful for spin-waiting that does not require nanosecond precision. This uses the new TPAUSE instruction introduced on Intel's newest processors as part of the waitpkg instructions. For CPUs that do not support waitpkg instructions, this is equivalent to yield(). Co-Authored-By: liamwhite --- src/common/x64/cpu_wait.cpp | 72 +++++++++++++++++++++++++++++++++++++++++++++ src/common/x64/cpu_wait.h | 10 +++++++ 2 files changed, 82 insertions(+) create mode 100644 src/common/x64/cpu_wait.cpp create mode 100644 src/common/x64/cpu_wait.h (limited to 'src/common/x64') diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp new file mode 100644 index 000000000..1fab0bfe8 --- /dev/null +++ b/src/common/x64/cpu_wait.cpp @@ -0,0 +1,72 @@ +// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#include + +#ifdef _MSC_VER +#include +#endif + +#include "common/x64/cpu_detect.h" +#include "common/x64/cpu_wait.h" + +namespace Common::X64 { + +#ifdef _MSC_VER +__forceinline static u64 FencedRDTSC() { + _mm_lfence(); + _ReadWriteBarrier(); + const u64 result = __rdtsc(); + _mm_lfence(); + _ReadWriteBarrier(); + return result; +} + +__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); +} +#else +static u64 FencedRDTSC() { + u64 result; + asm volatile("lfence\n\t" + "rdtsc\n\t" + "shl $32, %%rdx\n\t" + "or %%rdx, %0\n\t" + "lfence" + : "=a"(result) + : + : "rdx", "memory", "cc"); + return result; +} + +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(tsc & 0xFFFFFFFF); + const auto edx = static_cast(tsc >> 32); + asm volatile("tpause %0" : : "r"(0), "d"(edx), "a"(eax)); +} +#endif + +void MicroSleep() { + static const bool has_waitpkg = GetCPUCaps().waitpkg; + + if (has_waitpkg) { + TPAUSE(); + } else { + std::this_thread::yield(); + } +} + +} // namespace Common::X64 diff --git a/src/common/x64/cpu_wait.h b/src/common/x64/cpu_wait.h new file mode 100644 index 000000000..99d3757a7 --- /dev/null +++ b/src/common/x64/cpu_wait.h @@ -0,0 +1,10 @@ +// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#pragma once + +namespace Common::X64 { + +void MicroSleep(); + +} // namespace Common::X64 -- cgit v1.2.3 From 981bc8aa1c924eabc55f63f9671324c548c72d59 Mon Sep 17 00:00:00 2001 From: Morph <39850852+Morph1984@users.noreply.github.com> Date: Wed, 22 Mar 2023 16:40:41 -0400 Subject: x64: Simplify RDTSC on non-MSVC compilers Co-Authored-By: liamwhite --- src/common/x64/cpu_wait.cpp | 13 +++++-------- src/common/x64/native_clock.cpp | 13 +++++-------- 2 files changed, 10 insertions(+), 16 deletions(-) (limited to 'src/common/x64') diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp index 1fab0bfe8..cfeef6a3d 100644 --- a/src/common/x64/cpu_wait.cpp +++ b/src/common/x64/cpu_wait.cpp @@ -33,16 +33,13 @@ __forceinline static void TPAUSE() { } #else static u64 FencedRDTSC() { - u64 result; + u64 eax; + u64 edx; asm volatile("lfence\n\t" "rdtsc\n\t" - "shl $32, %%rdx\n\t" - "or %%rdx, %0\n\t" - "lfence" - : "=a"(result) - : - : "rdx", "memory", "cc"); - return result; + "lfence\n\t" + : "=a"(eax), "=d"(edx)); + return (edx << 32) | eax; } static void TPAUSE() { diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp index 76c66e7ee..277b00662 100644 --- a/src/common/x64/native_clock.cpp +++ b/src/common/x64/native_clock.cpp @@ -27,16 +27,13 @@ __forceinline static u64 FencedRDTSC() { } #else static u64 FencedRDTSC() { - u64 result; + u64 eax; + u64 edx; asm volatile("lfence\n\t" "rdtsc\n\t" - "shl $32, %%rdx\n\t" - "or %%rdx, %0\n\t" - "lfence" - : "=a"(result) - : - : "rdx", "memory", "cc"); - return result; + "lfence\n\t" + : "=a"(eax), "=d"(edx)); + return (edx << 32) | eax; } #endif -- cgit v1.2.3