Merge pull request #3416 from FernandoS27/schedule

Kernel: Refactors and Implement a TimeManager and SchedulerLocks

src/core/CMakeLists.txt

@@ -187,6 +187,8 @@ add_library(core STATIC
     hle/kernel/synchronization.h
     hle/kernel/thread.cpp
     hle/kernel/thread.h
+    hle/kernel/time_manager.cpp
+    hle/kernel/time_manager.h
     hle/kernel/transfer_memory.cpp
     hle/kernel/transfer_memory.h
     hle/kernel/vm_manager.cpp

src/core/core.cpp

@@ -707,4 +707,12 @@ const Service::SM::ServiceManager& System::ServiceManager() const {
     return *impl->service_manager;
 }
 
+void System::RegisterCoreThread(std::size_t id) {
+    impl->kernel.RegisterCoreThread(id);
+}
+
+void System::RegisterHostThread() {
+    impl->kernel.RegisterHostThread();
+}
+
 } // namespace Core

src/core/core.h

@@ -360,6 +360,12 @@ public:
 
     const CurrentBuildProcessID& GetCurrentProcessBuildID() const;
 
+    /// Register a host thread as an emulated CPU Core.
+    void RegisterCoreThread(std::size_t id);
+
+    /// Register a host thread as an auxiliary thread.
+    void RegisterHostThread();
+
 private:
     System();
 

src/core/hardware_properties.h

@@ -20,6 +20,8 @@ constexpr u32 NUM_CPU_CORES = 4;            // Number of CPU Cores
 
 } // namespace Hardware
 
+constexpr u32 INVALID_HOST_THREAD_ID = 0xFFFFFFFF;
+
 struct EmuThreadHandle {
     u32 host_handle;
     u32 guest_handle;

src/core/hle/kernel/kernel.cpp

@@ -3,9 +3,12 @@
 // Refer to the license.txt file included.
 
 #include <atomic>
+#include <bitset>
 #include <functional>
 #include <memory>
 #include <mutex>
+#include <thread>
+#include <unordered_map>
 #include <utility>
 
 #include "common/assert.h"
@@ -15,6 +18,7 @@
 #include "core/core.h"
 #include "core/core_timing.h"
 #include "core/core_timing_util.h"
+#include "core/hardware_properties.h"
 #include "core/hle/kernel/client_port.h"
 #include "core/hle/kernel/errors.h"
 #include "core/hle/kernel/handle_table.h"
@@ -25,6 +29,7 @@
 #include "core/hle/kernel/scheduler.h"
 #include "core/hle/kernel/synchronization.h"
 #include "core/hle/kernel/thread.h"
+#include "core/hle/kernel/time_manager.h"
 #include "core/hle/lock.h"
 #include "core/hle/result.h"
 #include "core/memory.h"
@@ -44,7 +49,7 @@ static void ThreadWakeupCallback(u64 thread_handle, [[maybe_unused]] s64 cycles_
     std::lock_guard lock{HLE::g_hle_lock};
 
     std::shared_ptr<Thread> thread =
-        system.Kernel().RetrieveThreadFromWakeupCallbackHandleTable(proper_handle);
+        system.Kernel().RetrieveThreadFromGlobalHandleTable(proper_handle);
     if (thread == nullptr) {
         LOG_CRITICAL(Kernel, "Callback fired for invalid thread {:08X}", proper_handle);
         return;
@@ -97,8 +102,8 @@ static void ThreadWakeupCallback(u64 thread_handle, [[maybe_unused]] s64 cycles_
 }
 
 struct KernelCore::Impl {
-    explicit Impl(Core::System& system)
-        : system{system}, global_scheduler{system}, synchronization{system} {}
+    explicit Impl(Core::System& system, KernelCore& kernel)
+        : system{system}, global_scheduler{kernel}, synchronization{system}, time_manager{system} {}
 
     void Initialize(KernelCore& kernel) {
         Shutdown();
@@ -120,7 +125,7 @@ struct KernelCore::Impl {
 
         system_resource_limit = nullptr;
 
-        thread_wakeup_callback_handle_table.Clear();
+        global_handle_table.Clear();
         thread_wakeup_event_type = nullptr;
         preemption_event = nullptr;
 
@@ -138,8 +143,8 @@ struct KernelCore::Impl {
 
     void InitializePhysicalCores() {
         exclusive_monitor =
-            Core::MakeExclusiveMonitor(system.Memory(), global_scheduler.CpuCoresCount());
-        for (std::size_t i = 0; i < global_scheduler.CpuCoresCount(); i++) {
+            Core::MakeExclusiveMonitor(system.Memory(), Core::Hardware::NUM_CPU_CORES);
+        for (std::size_t i = 0; i < Core::Hardware::NUM_CPU_CORES; i++) {
             cores.emplace_back(system, i, *exclusive_monitor);
         }
     }
@@ -184,6 +189,50 @@ struct KernelCore::Impl {
         system.Memory().SetCurrentPageTable(*process);
     }
 
+    void RegisterCoreThread(std::size_t core_id) {
+        std::unique_lock lock{register_thread_mutex};
+        const std::thread::id this_id = std::this_thread::get_id();
+        const auto it = host_thread_ids.find(this_id);
+        ASSERT(core_id < Core::Hardware::NUM_CPU_CORES);
+        ASSERT(it == host_thread_ids.end());
+        ASSERT(!registered_core_threads[core_id]);
+        host_thread_ids[this_id] = static_cast<u32>(core_id);
+        registered_core_threads.set(core_id);
+    }
+
+    void RegisterHostThread() {
+        std::unique_lock lock{register_thread_mutex};
+        const std::thread::id this_id = std::this_thread::get_id();
+        const auto it = host_thread_ids.find(this_id);
+        ASSERT(it == host_thread_ids.end());
+        host_thread_ids[this_id] = registered_thread_ids++;
+    }
+
+    u32 GetCurrentHostThreadID() const {
+        const std::thread::id this_id = std::this_thread::get_id();
+        const auto it = host_thread_ids.find(this_id);
+        if (it == host_thread_ids.end()) {
+            return Core::INVALID_HOST_THREAD_ID;
+        }
+        return it->second;
+    }
+
+    Core::EmuThreadHandle GetCurrentEmuThreadID() const {
+        Core::EmuThreadHandle result = Core::EmuThreadHandle::InvalidHandle();
+        result.host_handle = GetCurrentHostThreadID();
+        if (result.host_handle >= Core::Hardware::NUM_CPU_CORES) {
+            return result;
+        }
+        const Kernel::Scheduler& sched = cores[result.host_handle].Scheduler();
+        const Kernel::Thread* current = sched.GetCurrentThread();
+        if (current != nullptr) {
+            result.guest_handle = current->GetGlobalHandle();
+        } else {
+            result.guest_handle = InvalidHandle;
+        }
+        return result;
+    }
+
     std::atomic<u32> next_object_id{0};
     std::atomic<u64> next_kernel_process_id{Process::InitialKIPIDMin};
     std::atomic<u64> next_user_process_id{Process::ProcessIDMin};
@@ -194,15 +243,16 @@ struct KernelCore::Impl {
     Process* current_process = nullptr;
     Kernel::GlobalScheduler global_scheduler;
     Kernel::Synchronization synchronization;
+    Kernel::TimeManager time_manager;
 
     std::shared_ptr<ResourceLimit> system_resource_limit;
 
     std::shared_ptr<Core::Timing::EventType> thread_wakeup_event_type;
     std::shared_ptr<Core::Timing::EventType> preemption_event;
 
-    // TODO(yuriks): This can be removed if Thread objects are explicitly pooled in the future,
-    // allowing us to simply use a pool index or similar.
-    Kernel::HandleTable thread_wakeup_callback_handle_table;
+    // This is the kernel's handle table or supervisor handle table which
+    // stores all the objects in place.
+    Kernel::HandleTable global_handle_table;
 
     /// Map of named ports managed by the kernel, which can be retrieved using
     /// the ConnectToPort SVC.
@@ -211,11 +261,17 @@ struct KernelCore::Impl {
     std::unique_ptr<Core::ExclusiveMonitor> exclusive_monitor;
     std::vector<Kernel::PhysicalCore> cores;
 
+    // 0-3 IDs represent core threads, >3 represent others
+    std::unordered_map<std::thread::id, u32> host_thread_ids;
+    u32 registered_thread_ids{Core::Hardware::NUM_CPU_CORES};
+    std::bitset<Core::Hardware::NUM_CPU_CORES> registered_core_threads;
+    std::mutex register_thread_mutex;
+
     // System context
     Core::System& system;
 };
 
-KernelCore::KernelCore(Core::System& system) : impl{std::make_unique<Impl>(system)} {}
+KernelCore::KernelCore(Core::System& system) : impl{std::make_unique<Impl>(system, *this)} {}
 KernelCore::~KernelCore() {
     Shutdown();
 }
@@ -232,9 +288,8 @@ std::shared_ptr<ResourceLimit> KernelCore::GetSystemResourceLimit() const {
     return impl->system_resource_limit;
 }
 
-std::shared_ptr<Thread> KernelCore::RetrieveThreadFromWakeupCallbackHandleTable(
-    Handle handle) const {
-    return impl->thread_wakeup_callback_handle_table.Get<Thread>(handle);
+std::shared_ptr<Thread> KernelCore::RetrieveThreadFromGlobalHandleTable(Handle handle) const {
+    return impl->global_handle_table.Get<Thread>(handle);
 }
 
 void KernelCore::AppendNewProcess(std::shared_ptr<Process> process) {
@@ -265,6 +320,14 @@ const Kernel::GlobalScheduler& KernelCore::GlobalScheduler() const {
     return impl->global_scheduler;
 }
 
+Kernel::Scheduler& KernelCore::Scheduler(std::size_t id) {
+    return impl->cores[id].Scheduler();
+}
+
+const Kernel::Scheduler& KernelCore::Scheduler(std::size_t id) const {
+    return impl->cores[id].Scheduler();
+}
+
 Kernel::PhysicalCore& KernelCore::PhysicalCore(std::size_t id) {
     return impl->cores[id];
 }
@@ -281,6 +344,14 @@ const Kernel::Synchronization& KernelCore::Synchronization() const {
     return impl->synchronization;
 }
 
+Kernel::TimeManager& KernelCore::TimeManager() {
+    return impl->time_manager;
+}
+
+const Kernel::TimeManager& KernelCore::TimeManager() const {
+    return impl->time_manager;
+}
+
 Core::ExclusiveMonitor& KernelCore::GetExclusiveMonitor() {
     return *impl->exclusive_monitor;
 }
@@ -338,12 +409,28 @@ const std::shared_ptr<Core::Timing::EventType>& KernelCore::ThreadWakeupCallback
     return impl->thread_wakeup_event_type;
 }
 
-Kernel::HandleTable& KernelCore::ThreadWakeupCallbackHandleTable() {
-    return impl->thread_wakeup_callback_handle_table;
+Kernel::HandleTable& KernelCore::GlobalHandleTable() {
+    return impl->global_handle_table;
 }
 
-const Kernel::HandleTable& KernelCore::ThreadWakeupCallbackHandleTable() const {
-    return impl->thread_wakeup_callback_handle_table;
+const Kernel::HandleTable& KernelCore::GlobalHandleTable() const {
+    return impl->global_handle_table;
+}
+
+void KernelCore::RegisterCoreThread(std::size_t core_id) {
+    impl->RegisterCoreThread(core_id);
+}
+
+void KernelCore::RegisterHostThread() {
+    impl->RegisterHostThread();
+}
+
+u32 KernelCore::GetCurrentHostThreadID() const {
+    return impl->GetCurrentHostThreadID();
+}
+
+Core::EmuThreadHandle KernelCore::GetCurrentEmuThreadID() const {
+    return impl->GetCurrentEmuThreadID();
 }
 
 } // namespace Kernel

src/core/hle/kernel/kernel.h

@@ -11,6 +11,7 @@
 #include "core/hle/kernel/object.h"
 
 namespace Core {
+struct EmuThreadHandle;
 class ExclusiveMonitor;
 class System;
 } // namespace Core
@@ -29,8 +30,10 @@ class HandleTable;
 class PhysicalCore;
 class Process;
 class ResourceLimit;
+class Scheduler;
 class Synchronization;
 class Thread;
+class TimeManager;
 
 /// Represents a single instance of the kernel.
 class KernelCore {
@@ -64,7 +67,7 @@ public:
     std::shared_ptr<ResourceLimit> GetSystemResourceLimit() const;
 
     /// Retrieves a shared pointer to a Thread instance within the thread wakeup handle table.
-    std::shared_ptr<Thread> RetrieveThreadFromWakeupCallbackHandleTable(Handle handle) const;
+    std::shared_ptr<Thread> RetrieveThreadFromGlobalHandleTable(Handle handle) const;
 
     /// Adds the given shared pointer to an internal list of active processes.
     void AppendNewProcess(std::shared_ptr<Process> process);
@@ -87,6 +90,12 @@ public:
     /// Gets the sole instance of the global scheduler
     const Kernel::GlobalScheduler& GlobalScheduler() const;
 
+    /// Gets the sole instance of the Scheduler assoviated with cpu core 'id'
+    Kernel::Scheduler& Scheduler(std::size_t id);
+
+    /// Gets the sole instance of the Scheduler assoviated with cpu core 'id'
+    const Kernel::Scheduler& Scheduler(std::size_t id) const;
+
     /// Gets the an instance of the respective physical CPU core.
     Kernel::PhysicalCore& PhysicalCore(std::size_t id);
 
@@ -99,6 +108,12 @@ public:
     /// Gets the an instance of the Synchronization Interface.
     const Kernel::Synchronization& Synchronization() const;
 
+    /// Gets the an instance of the TimeManager Interface.
+    Kernel::TimeManager& TimeManager();
+
+    /// Gets the an instance of the TimeManager Interface.
+    const Kernel::TimeManager& TimeManager() const;
+
     /// Stops execution of 'id' core, in order to reschedule a new thread.
     void PrepareReschedule(std::size_t id);
 
@@ -120,6 +135,18 @@ public:
     /// Determines whether or not the given port is a valid named port.
     bool IsValidNamedPort(NamedPortTable::const_iterator port) const;
 
+    /// Gets the current host_thread/guest_thread handle.
+    Core::EmuThreadHandle GetCurrentEmuThreadID() const;
+
+    /// Gets the current host_thread handle.
+    u32 GetCurrentHostThreadID() const;
+
+    /// Register the current thread as a CPU Core Thread.
+    void RegisterCoreThread(std::size_t core_id);
+
+    /// Register the current thread as a non CPU core thread.
+    void RegisterHostThread();
+
 private:
     friend class Object;
     friend class Process;
@@ -140,11 +167,11 @@ private:
     /// Retrieves the event type used for thread wakeup callbacks.
     const std::shared_ptr<Core::Timing::EventType>& ThreadWakeupCallbackEventType() const;
 
-    /// Provides a reference to the thread wakeup callback handle table.
-    Kernel::HandleTable& ThreadWakeupCallbackHandleTable();
+    /// Provides a reference to the global handle table.
+    Kernel::HandleTable& GlobalHandleTable();
 
-    /// Provides a const reference to the thread wakeup callback handle table.
-    const Kernel::HandleTable& ThreadWakeupCallbackHandleTable() const;
+    /// Provides a const reference to the global handle table.
+    const Kernel::HandleTable& GlobalHandleTable() const;
 
     struct Impl;
     std::unique_ptr<Impl> impl;

src/core/hle/kernel/scheduler.cpp

@@ -18,10 +18,11 @@
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/process.h"
 #include "core/hle/kernel/scheduler.h"
+#include "core/hle/kernel/time_manager.h"
 
 namespace Kernel {
 
-GlobalScheduler::GlobalScheduler(Core::System& system) : system{system} {}
+GlobalScheduler::GlobalScheduler(KernelCore& kernel) : kernel{kernel} {}
 
 GlobalScheduler::~GlobalScheduler() = default;
 
@@ -35,7 +36,7 @@ void GlobalScheduler::RemoveThread(std::shared_ptr<Thread> thread) {
 }
 
 void GlobalScheduler::UnloadThread(std::size_t core) {
-    Scheduler& sched = system.Scheduler(core);
+    Scheduler& sched = kernel.Scheduler(core);
     sched.UnloadThread();
 }
 
@@ -50,7 +51,7 @@ void GlobalScheduler::SelectThread(std::size_t core) {
         sched.is_context_switch_pending = sched.selected_thread != sched.current_thread;
         std::atomic_thread_fence(std::memory_order_seq_cst);
     };
-    Scheduler& sched = system.Scheduler(core);
+    Scheduler& sched = kernel.Scheduler(core);
     Thread* current_thread = nullptr;
     // Step 1: Get top thread in schedule queue.
     current_thread = scheduled_queue[core].empty() ? nullptr : scheduled_queue[core].front();
@@ -356,6 +357,32 @@ void GlobalScheduler::Shutdown() {
     thread_list.clear();
 }
 
+void GlobalScheduler::Lock() {
+    Core::EmuThreadHandle current_thread = kernel.GetCurrentEmuThreadID();
+    if (current_thread == current_owner) {
+        ++scope_lock;
+    } else {
+        inner_lock.lock();
+        current_owner = current_thread;
+        ASSERT(current_owner != Core::EmuThreadHandle::InvalidHandle());
+        scope_lock = 1;
+    }
+}
+
+void GlobalScheduler::Unlock() {
+    if (--scope_lock != 0) {
+        ASSERT(scope_lock > 0);
+        return;
+    }
+    for (std::size_t i = 0; i < Core::Hardware::NUM_CPU_CORES; i++) {
+        SelectThread(i);
+    }
+    current_owner = Core::EmuThreadHandle::InvalidHandle();
+    scope_lock = 1;
+    inner_lock.unlock();
+    // TODO(Blinkhawk): Setup the interrupts and change context on current core.
+}
+
 Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, std::size_t core_id)
     : system(system), cpu_core(cpu_core), core_id(core_id) {}
 
@@ -485,4 +512,27 @@ void Scheduler::Shutdown() {
     selected_thread = nullptr;
 }
 
+SchedulerLock::SchedulerLock(KernelCore& kernel) : kernel{kernel} {
+    kernel.GlobalScheduler().Lock();
+}
+
+SchedulerLock::~SchedulerLock() {
+    kernel.GlobalScheduler().Unlock();
+}
+
+SchedulerLockAndSleep::SchedulerLockAndSleep(KernelCore& kernel, Handle& event_handle,
+                                             Thread* time_task, s64 nanoseconds)
+    : SchedulerLock{kernel}, event_handle{event_handle}, time_task{time_task}, nanoseconds{
+                                                                                   nanoseconds} {
+    event_handle = InvalidHandle;
+}
+
+SchedulerLockAndSleep::~SchedulerLockAndSleep() {
+    if (sleep_cancelled) {
+        return;
+    }
+    auto& time_manager = kernel.TimeManager();
+    time_manager.ScheduleTimeEvent(event_handle, time_task, nanoseconds);
+}
+
 } // namespace Kernel

src/core/hle/kernel/scheduler.h

@@ -6,6 +6,7 @@
 
 #include <atomic>
 #include <memory>
+#include <mutex>
 #include <vector>
 
 #include "common/common_types.h"
@@ -20,11 +21,13 @@ class System;
 
 namespace Kernel {
 
+class KernelCore;
 class Process;
+class SchedulerLock;
 
 class GlobalScheduler final {
 public:
-    explicit GlobalScheduler(Core::System& system);
+    explicit GlobalScheduler(KernelCore& kernel);
     ~GlobalScheduler();
 
     /// Adds a new thread to the scheduler
@@ -138,6 +141,14 @@ public:
     void Shutdown();
 
 private:
+    friend class SchedulerLock;
+
+    /// Lock the scheduler to the current thread.
+    void Lock();
+
+    /// Unlocks the scheduler, reselects threads, interrupts cores for rescheduling
+    /// and reschedules current core if needed.
+    void Unlock();
     /**
      * Transfers a thread into an specific core. If the destination_core is -1
      * it will be unscheduled from its source code and added into its suggested
@@ -158,9 +169,14 @@ private:
     // ordered from Core 0 to Core 3.
     std::array<u32, Core::Hardware::NUM_CPU_CORES> preemption_priorities = {59, 59, 59, 62};
 
+    /// Scheduler lock mechanisms.
+    std::mutex inner_lock{}; // TODO(Blinkhawk): Replace for a SpinLock
+    std::atomic<s64> scope_lock{};
+    Core::EmuThreadHandle current_owner{Core::EmuThreadHandle::InvalidHandle()};
+
     /// Lists all thread ids that aren't deleted/etc.
     std::vector<std::shared_ptr<Thread>> thread_list;
-    Core::System& system;
+    KernelCore& kernel;
 };
 
 class Scheduler final {
@@ -227,4 +243,30 @@ private:
     bool is_context_switch_pending = false;
 };
 
+class SchedulerLock {
+public:
+    explicit SchedulerLock(KernelCore& kernel);
+    ~SchedulerLock();
+
+protected:
+    KernelCore& kernel;
+};
+
+class SchedulerLockAndSleep : public SchedulerLock {
+public:
+    explicit SchedulerLockAndSleep(KernelCore& kernel, Handle& event_handle, Thread* time_task,
+                                   s64 nanoseconds);
+    ~SchedulerLockAndSleep();
+
+    void CancelSleep() {
+        sleep_cancelled = true;
+    }
+
+private:
+    Handle& event_handle;
+    Thread* time_task;
+    s64 nanoseconds;
+    bool sleep_cancelled{};
+};
+
 } // namespace Kernel

src/core/hle/kernel/thread.cpp

@@ -46,9 +46,9 @@ Thread::~Thread() = default;
 void Thread::Stop() {
     // Cancel any outstanding wakeup events for this thread
     Core::System::GetInstance().CoreTiming().UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(),
-                                                             callback_handle);
-    kernel.ThreadWakeupCallbackHandleTable().Close(callback_handle);
-    callback_handle = 0;
+                                                             global_handle);
+    kernel.GlobalHandleTable().Close(global_handle);
+    global_handle = 0;
     SetStatus(ThreadStatus::Dead);
     Signal();
 
@@ -73,12 +73,12 @@ void Thread::WakeAfterDelay(s64 nanoseconds) {
     // thread-safe version of ScheduleEvent.
     const s64 cycles = Core::Timing::nsToCycles(std::chrono::nanoseconds{nanoseconds});
     Core::System::GetInstance().CoreTiming().ScheduleEvent(
-        cycles, kernel.ThreadWakeupCallbackEventType(), callback_handle);
+        cycles, kernel.ThreadWakeupCallbackEventType(), global_handle);
 }
 
 void Thread::CancelWakeupTimer() {
     Core::System::GetInstance().CoreTiming().UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(),
-                                                             callback_handle);
+                                                             global_handle);
 }
 
 void Thread::ResumeFromWait() {
@@ -190,7 +190,7 @@ ResultVal<std::shared_ptr<Thread>> Thread::Create(KernelCore& kernel, std::strin
     thread->condvar_wait_address = 0;
     thread->wait_handle = 0;
     thread->name = std::move(name);
-    thread->callback_handle = kernel.ThreadWakeupCallbackHandleTable().Create(thread).Unwrap();
+    thread->global_handle = kernel.GlobalHandleTable().Create(thread).Unwrap();
     thread->owner_process = &owner_process;
     auto& scheduler = kernel.GlobalScheduler();
     scheduler.AddThread(thread);

src/core/hle/kernel/thread.h

@@ -453,6 +453,10 @@ public:
         is_sync_cancelled = value;
     }
 
+    Handle GetGlobalHandle() const {
+        return global_handle;
+    }
+
 private:
     void SetSchedulingStatus(ThreadSchedStatus new_status);
     void SetCurrentPriority(u32 new_priority);
@@ -514,7 +518,7 @@ private:
     VAddr arb_wait_address{0};
 
     /// Handle used as userdata to reference this object when inserting into the CoreTiming queue.
-    Handle callback_handle = 0;
+    Handle global_handle = 0;
 
     /// Callback that will be invoked when the thread is resumed from a waiting state. If the thread
     /// was waiting via WaitSynchronization then the object will be the last object that became

src/core/hle/kernel/time_manager.cpp

@@ -0,0 +1,44 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "core/core.h"
+#include "core/core_timing.h"
+#include "core/core_timing_util.h"
+#include "core/hle/kernel/handle_table.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/thread.h"
+#include "core/hle/kernel/time_manager.h"
+
+namespace Kernel {
+
+TimeManager::TimeManager(Core::System& system) : system{system} {
+    time_manager_event_type = Core::Timing::CreateEvent(
+        "Kernel::TimeManagerCallback", [this](u64 thread_handle, [[maybe_unused]] s64 cycles_late) {
+            Handle proper_handle = static_cast<Handle>(thread_handle);
+            std::shared_ptr<Thread> thread =
+                this->system.Kernel().RetrieveThreadFromGlobalHandleTable(proper_handle);
+            thread->ResumeFromWait();
+        });
+}
+
+void TimeManager::ScheduleTimeEvent(Handle& event_handle, Thread* timetask, s64 nanoseconds) {
+    if (nanoseconds > 0) {
+        ASSERT(timetask);
+        event_handle = timetask->GetGlobalHandle();
+        const s64 cycles = Core::Timing::nsToCycles(std::chrono::nanoseconds{nanoseconds});
+        system.CoreTiming().ScheduleEvent(cycles, time_manager_event_type, event_handle);
+    } else {
+        event_handle = InvalidHandle;
+    }
+}
+
+void TimeManager::UnscheduleTimeEvent(Handle event_handle) {
+    if (event_handle == InvalidHandle) {
+        return;
+    }
+    system.CoreTiming().UnscheduleEvent(time_manager_event_type, event_handle);
+}
+
+} // namespace Kernel

src/core/hle/kernel/time_manager.h

@@ -0,0 +1,43 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+
+#include "core/hle/kernel/object.h"
+
+namespace Core {
+class System;
+} // namespace Core
+
+namespace Core::Timing {
+struct EventType;
+} // namespace Core::Timing
+
+namespace Kernel {
+
+class Thread;
+
+/**
+ * The `TimeManager` takes care of scheduling time events on threads and executes their TimeUp
+ * method when the event is triggered.
+ */
+class TimeManager {
+public:
+    explicit TimeManager(Core::System& system);
+
+    /// Schedule a time event on `timetask` thread that will expire in 'nanoseconds'
+    /// returns a non-invalid handle in `event_handle` if correctly scheduled
+    void ScheduleTimeEvent(Handle& event_handle, Thread* timetask, s64 nanoseconds);
+
+    /// Unschedule an existing time event
+    void UnscheduleTimeEvent(Handle event_handle);
+
+private:
+    Core::System& system;
+    std::shared_ptr<Core::Timing::EventType> time_manager_event_type;
+};
+
+} // namespace Kernel