From af022294dd7240a3199794e43dd8997fd0dbc136 Mon Sep 17 00:00:00 2001 From: Liam Date: Fri, 27 May 2022 20:44:45 -0400 Subject: CpuManager: simplify pausing --- src/core/cpu_manager.cpp | 116 +++++++++++++---------------------------------- 1 file changed, 32 insertions(+), 84 deletions(-) (limited to 'src/core/cpu_manager.cpp') diff --git a/src/core/cpu_manager.cpp b/src/core/cpu_manager.cpp index 09d9c5163..b4718fbbe 100644 --- a/src/core/cpu_manager.cpp +++ b/src/core/cpu_manager.cpp @@ -16,7 +16,8 @@ namespace Core { -CpuManager::CpuManager(System& system_) : system{system_} {} +CpuManager::CpuManager(System& system_) + : pause_barrier{std::make_unique(1)}, system{system_} {} CpuManager::~CpuManager() = default; void CpuManager::ThreadStart(std::stop_token stop_token, CpuManager& cpu_manager, @@ -30,8 +31,10 @@ void CpuManager::Initialize() { for (std::size_t core = 0; core < Core::Hardware::NUM_CPU_CORES; core++) { core_data[core].host_thread = std::jthread(ThreadStart, std::ref(*this), core); } + pause_barrier = std::make_unique(Core::Hardware::NUM_CPU_CORES + 1); } else { core_data[0].host_thread = std::jthread(ThreadStart, std::ref(*this), 0); + pause_barrier = std::make_unique(2); } } @@ -138,51 +141,14 @@ void CpuManager::MultiCoreRunSuspendThread() { auto core = kernel.CurrentPhysicalCoreIndex(); auto& scheduler = *kernel.CurrentScheduler(); Kernel::KThread* current_thread = scheduler.GetCurrentThread(); + current_thread->DisableDispatch(); + Common::Fiber::YieldTo(current_thread->GetHostContext(), *core_data[core].host_context); - ASSERT(scheduler.ContextSwitchPending()); ASSERT(core == kernel.CurrentPhysicalCoreIndex()); scheduler.RescheduleCurrentCore(); } } -void CpuManager::MultiCorePause(bool paused) { - if (!paused) { - bool all_not_barrier = false; - while (!all_not_barrier) { - all_not_barrier = true; - for (const auto& data : core_data) { - all_not_barrier &= !data.is_running.load() && data.initialized.load(); - } - } - for (auto& data : core_data) { - data.enter_barrier->Set(); - } - if (paused_state.load()) { - bool all_barrier = false; - while (!all_barrier) { - all_barrier = true; - for (const auto& data : core_data) { - all_barrier &= data.is_paused.load() && data.initialized.load(); - } - } - for (auto& data : core_data) { - data.exit_barrier->Set(); - } - } - } else { - /// Wait until all cores are paused. - bool all_barrier = false; - while (!all_barrier) { - all_barrier = true; - for (const auto& data : core_data) { - all_barrier &= data.is_paused.load() && data.initialized.load(); - } - } - /// Don't release the barrier - } - paused_state = paused; -} - /////////////////////////////////////////////////////////////////////////////// /// SingleCore /// /////////////////////////////////////////////////////////////////////////////// @@ -235,8 +201,9 @@ void CpuManager::SingleCoreRunSuspendThread() { auto core = kernel.GetCurrentHostThreadID(); auto& scheduler = *kernel.CurrentScheduler(); Kernel::KThread* current_thread = scheduler.GetCurrentThread(); + current_thread->DisableDispatch(); + Common::Fiber::YieldTo(current_thread->GetHostContext(), *core_data[0].host_context); - ASSERT(scheduler.ContextSwitchPending()); ASSERT(core == kernel.GetCurrentHostThreadID()); scheduler.RescheduleCurrentCore(); } @@ -274,37 +241,21 @@ void CpuManager::PreemptSingleCore(bool from_running_enviroment) { } } -void CpuManager::SingleCorePause(bool paused) { - if (!paused) { - bool all_not_barrier = false; - while (!all_not_barrier) { - all_not_barrier = !core_data[0].is_running.load() && core_data[0].initialized.load(); - } - core_data[0].enter_barrier->Set(); - if (paused_state.load()) { - bool all_barrier = false; - while (!all_barrier) { - all_barrier = core_data[0].is_paused.load() && core_data[0].initialized.load(); - } - core_data[0].exit_barrier->Set(); - } - } else { - /// Wait until all cores are paused. - bool all_barrier = false; - while (!all_barrier) { - all_barrier = core_data[0].is_paused.load() && core_data[0].initialized.load(); - } - /// Don't release the barrier - } - paused_state = paused; -} - void CpuManager::Pause(bool paused) { - if (is_multicore) { - MultiCorePause(paused); - } else { - SingleCorePause(paused); + std::scoped_lock lk{pause_lock}; + + if (pause_state == paused) { + return; } + + // Set the new state + pause_state.store(paused); + + // Wake up any waiting threads + pause_state.notify_all(); + + // Wait for all threads to successfully change state before returning + pause_barrier->Sync(); } void CpuManager::RunThread(std::stop_token stop_token, std::size_t core) { @@ -320,27 +271,29 @@ void CpuManager::RunThread(std::stop_token stop_token, std::size_t core) { Common::SetCurrentThreadName(name.c_str()); Common::SetCurrentThreadPriority(Common::ThreadPriority::High); auto& data = core_data[core]; - data.enter_barrier = std::make_unique(); - data.exit_barrier = std::make_unique(); data.host_context = Common::Fiber::ThreadToFiber(); - data.is_running = false; - data.initialized = true; const bool sc_sync = !is_async_gpu && !is_multicore; bool sc_sync_first_use = sc_sync; // Cleanup SCOPE_EXIT({ data.host_context->Exit(); - data.enter_barrier.reset(); - data.exit_barrier.reset(); - data.initialized = false; MicroProfileOnThreadExit(); }); /// Running while (running_mode) { - data.is_running = false; - data.enter_barrier->Wait(); + if (pause_state.load(std::memory_order_relaxed)) { + // Wait for caller to acknowledge pausing + pause_barrier->Sync(); + + // Wait until unpaused + pause_state.wait(true, std::memory_order_relaxed); + + // Wait for caller to acknowledge unpausing + pause_barrier->Sync(); + } + if (sc_sync_first_use) { system.GPU().ObtainContext(); sc_sync_first_use = false; @@ -352,12 +305,7 @@ void CpuManager::RunThread(std::stop_token stop_token, std::size_t core) { } auto current_thread = system.Kernel().CurrentScheduler()->GetCurrentThread(); - data.is_running = true; Common::Fiber::YieldTo(data.host_context, *current_thread->GetHostContext()); - data.is_running = false; - data.is_paused = true; - data.exit_barrier->Wait(); - data.is_paused = false; } } -- cgit v1.2.3