From 5e746da9817f9fee8f0d182c6fcc766ccf816017 Mon Sep 17 00:00:00 2001 From: ameerj <52414509+ameerj@users.noreply.github.com> Date: Fri, 10 Feb 2023 20:43:06 -0500 Subject: [PATCH] kernel: Refactor thread_local variable usage On MSVC at least, there seems to be a non-trivial overhead to calling GetHostThreadId(). This slightly reworks the host_thread_id variable to reduce some of the complexity around its usage, along with some small refactors around current_thread and dummy thread --- src/core/hle/kernel/kernel.cpp | 43 ++++++++++++++-------------------- 1 file changed, 17 insertions(+), 26 deletions(-) diff --git a/src/core/hle/kernel/kernel.cpp b/src/core/hle/kernel/kernel.cpp index d9eafe2613..ece20a6439 100644 --- a/src/core/hle/kernel/kernel.cpp +++ b/src/core/hle/kernel/kernel.cpp @@ -367,23 +367,21 @@ struct KernelCore::Impl { current_process = process; } - static inline thread_local u32 host_thread_id = UINT32_MAX; + static inline thread_local u8 host_thread_id = UINT8_MAX; - /// Gets the host thread ID for the caller, allocating a new one if this is the first time - u32 GetHostThreadId(std::size_t core_id) { - if (host_thread_id == UINT32_MAX) { - // The first four slots are reserved for CPU core threads - ASSERT(core_id < Core::Hardware::NUM_CPU_CORES); - host_thread_id = static_cast(core_id); - } + /// Sets the host thread ID for the caller. + u32 SetHostThreadId(std::size_t core_id) { + // This should only be called during core init. + ASSERT(host_thread_id == UINT8_MAX); + + // The first four slots are reserved for CPU core threads + ASSERT(core_id < Core::Hardware::NUM_CPU_CORES); + host_thread_id = static_cast(core_id); return host_thread_id; } - /// Gets the host thread ID for the caller, allocating a new one if this is the first time - u32 GetHostThreadId() { - if (host_thread_id == UINT32_MAX) { - host_thread_id = next_host_thread_id++; - } + /// Gets the host thread ID for the caller + u32 GetHostThreadId() const { return host_thread_id; } @@ -391,23 +389,19 @@ struct KernelCore::Impl { KThread* GetHostDummyThread(KThread* existing_thread) { auto initialize = [this](KThread* thread) { ASSERT(KThread::InitializeDummyThread(thread, nullptr).IsSuccess()); - thread->SetName(fmt::format("DummyThread:{}", GetHostThreadId())); + thread->SetName(fmt::format("DummyThread:{}", next_host_thread_id++)); return thread; }; thread_local KThread raw_thread{system.Kernel()}; - thread_local KThread* thread = nullptr; - if (thread == nullptr) { - thread = (existing_thread == nullptr) ? initialize(&raw_thread) : existing_thread; - } - + thread_local KThread* thread = existing_thread ? existing_thread : initialize(&raw_thread); return thread; } /// Registers a CPU core thread by allocating a host thread ID for it void RegisterCoreThread(std::size_t core_id) { ASSERT(core_id < Core::Hardware::NUM_CPU_CORES); - const auto this_id = GetHostThreadId(core_id); + const auto this_id = SetHostThreadId(core_id); if (!is_multicore) { single_core_thread_id = this_id; } @@ -415,7 +409,6 @@ struct KernelCore::Impl { /// Registers a new host thread by allocating a host thread ID for it void RegisterHostThread(KThread* existing_thread) { - [[maybe_unused]] const auto this_id = GetHostThreadId(); [[maybe_unused]] const auto dummy_thread = GetHostDummyThread(existing_thread); } @@ -445,11 +438,9 @@ struct KernelCore::Impl { static inline thread_local KThread* current_thread{nullptr}; KThread* GetCurrentEmuThread() { - const auto thread_id = GetCurrentHostThreadID(); - if (thread_id >= Core::Hardware::NUM_CPU_CORES) { - return GetHostDummyThread(nullptr); + if (!current_thread) { + current_thread = GetHostDummyThread(nullptr); } - return current_thread; } @@ -1002,7 +993,7 @@ const Kernel::PhysicalCore& KernelCore::CurrentPhysicalCore() const { } Kernel::KScheduler* KernelCore::CurrentScheduler() { - u32 core_id = impl->GetCurrentHostThreadID(); + const u32 core_id = impl->GetCurrentHostThreadID(); if (core_id >= Core::Hardware::NUM_CPU_CORES) { // This is expected when called from not a guest thread return {};