5 files changed, 243 insertions, 43 deletions

diff --git a/src/common/thread.h b/src/common/thread.h
index 2fc071685..127cc7e23 100644
--- a/src/common/thread.h
+++ b/src/common/thread.h
@@ -9,6 +9,7 @@
 #include <cstddef>
 #include <mutex>
 #include <thread>
+#include "common/common_types.h"
 
 namespace Common {
 
@@ -28,8 +29,7 @@ public:
         is_set = false;
     }
 
-    template <class Duration>
-    bool WaitFor(const std::chrono::duration<Duration>& time) {
+    bool WaitFor(const std::chrono::nanoseconds& time) {
         std::unique_lock lk{mutex};
         if (!condvar.wait_for(lk, time, [this] { return is_set; }))
             return false;
diff --git a/src/core/host_timing.cpp b/src/core/host_timing.cpp
index c02f571c6..d9514b2c5 100644
--- a/src/core/host_timing.cpp
+++ b/src/core/host_timing.cpp
@@ -10,7 +10,6 @@
 #include <tuple>
 
 #include "common/assert.h"
-#include "common/thread.h"
 #include "core/core_timing_util.h"
 
 namespace Core::HostTiming {
@@ -47,39 +46,55 @@ void CoreTiming::Initialize() {
     event_fifo_id = 0;
     const auto empty_timed_callback = [](u64, s64) {};
     ev_lost = CreateEvent("_lost_event", empty_timed_callback);
-    start_time = std::chrono::system_clock::now();
+    start_time = std::chrono::steady_clock::now();
     timer_thread = std::make_unique<std::thread>(ThreadEntry, std::ref(*this));
 }
 
 void CoreTiming::Shutdown() {
-    std::unique_lock<std::mutex> guard(inner_mutex);
+    paused = true;
     shutting_down = true;
-    if (!is_set) {
-        is_set = true;
-        condvar.notify_one();
-    }
-    inner_mutex.unlock();
+    event.Set();
     timer_thread->join();
     ClearPendingEvents();
+    timer_thread.reset();
+    has_started = false;
+}
+
+void CoreTiming::Pause(bool is_paused) {
+    paused = is_paused;
+}
+
+void CoreTiming::SyncPause(bool is_paused) {
+    if (is_paused == paused && paused_set == paused) {
+        return;
+    }
+    Pause(is_paused);
+    event.Set();
+    while (paused_set != is_paused);
+}
+
+bool CoreTiming::IsRunning() {
+    return !paused_set;
+}
+
+bool CoreTiming::HasPendingEvents() {
+    return !(wait_set && event_queue.empty());
 }
 
 void CoreTiming::ScheduleEvent(s64 ns_into_future, const std::shared_ptr<EventType>& event_type,
                                u64 userdata) {
-    std::lock_guard guard{inner_mutex};
+    basic_lock.lock();
     const u64 timeout = static_cast<u64>(GetGlobalTimeNs().count() + ns_into_future);
 
     event_queue.emplace_back(Event{timeout, event_fifo_id++, userdata, event_type});
 
     std::push_heap(event_queue.begin(), event_queue.end(), std::greater<>());
-    if (!is_set) {
-        is_set = true;
-        condvar.notify_one();
-    }
+    basic_lock.unlock();
+    event.Set();
 }
 
 void CoreTiming::UnscheduleEvent(const std::shared_ptr<EventType>& event_type, u64 userdata) {
-    std::lock_guard guard{inner_mutex};
-
+    basic_lock.lock();
     const auto itr = std::remove_if(event_queue.begin(), event_queue.end(), [&](const Event& e) {
         return e.type.lock().get() == event_type.get() && e.userdata == userdata;
     });
@@ -89,6 +104,7 @@ void CoreTiming::UnscheduleEvent(const std::shared_ptr<EventType>& event_type, u
         event_queue.erase(itr, event_queue.end());
         std::make_heap(event_queue.begin(), event_queue.end(), std::greater<>());
     }
+    basic_lock.unlock();
 }
 
 u64 CoreTiming::GetCPUTicks() const {
@@ -106,7 +122,7 @@ void CoreTiming::ClearPendingEvents() {
 }
 
 void CoreTiming::RemoveEvent(const std::shared_ptr<EventType>& event_type) {
-    std::lock_guard guard{inner_mutex};
+    basic_lock.lock();
 
     const auto itr = std::remove_if(event_queue.begin(), event_queue.end(), [&](const Event& e) {
         return e.type.lock().get() == event_type.get();
@@ -117,43 +133,54 @@ void CoreTiming::RemoveEvent(const std::shared_ptr<EventType>& event_type) {
         event_queue.erase(itr, event_queue.end());
         std::make_heap(event_queue.begin(), event_queue.end(), std::greater<>());
     }
+    basic_lock.unlock();
 }
 
 void CoreTiming::Advance() {
-    while (true) {
-        std::unique_lock<std::mutex> guard(inner_mutex);
-
-        global_timer = GetGlobalTimeNs().count();
-
-        while (!event_queue.empty() && event_queue.front().time <= global_timer) {
-            Event evt = std::move(event_queue.front());
-            std::pop_heap(event_queue.begin(), event_queue.end(), std::greater<>());
-            event_queue.pop_back();
-            inner_mutex.unlock();
+    has_started = true;
+    while (!shutting_down) {
+        while (!paused) {
+            paused_set = false;
+            basic_lock.lock();
+            global_timer = GetGlobalTimeNs().count();
+
+            while (!event_queue.empty() && event_queue.front().time <= global_timer) {
+                Event evt = std::move(event_queue.front());
+                std::pop_heap(event_queue.begin(), event_queue.end(), std::greater<>());
+                event_queue.pop_back();
+                basic_lock.unlock();
+
+                if (auto event_type{evt.type.lock()}) {
+                    event_type->callback(evt.userdata, global_timer - evt.time);
+                }
+
+                basic_lock.lock();
+            }
 
-            if (auto event_type{evt.type.lock()}) {
-                event_type->callback(evt.userdata, global_timer - evt.time);
+            if (!event_queue.empty()) {
+                std::chrono::nanoseconds next_time = std::chrono::nanoseconds(event_queue.front().time - global_timer);
+                basic_lock.unlock();
+                event.WaitFor(next_time);
+            } else {
+                basic_lock.unlock();
+                wait_set = true;
+                event.Wait();
             }
 
-            inner_mutex.lock();
-        }
-        auto next_time = std::chrono::nanoseconds(event_queue.front().time - global_timer);
-        condvar.wait_for(guard, next_time, [this] { return is_set; });
-        is_set = false;
-        if (shutting_down) {
-            break;
+            wait_set = false;
         }
+        paused_set = true;
     }
 }
 
 std::chrono::nanoseconds CoreTiming::GetGlobalTimeNs() const {
-    sys_time_point current = std::chrono::system_clock::now();
+    sys_time_point current = std::chrono::steady_clock::now();
     auto elapsed = current - start_time;
     return std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed);
 }
 
 std::chrono::microseconds CoreTiming::GetGlobalTimeUs() const {
-    sys_time_point current = std::chrono::system_clock::now();
+    sys_time_point current = std::chrono::steady_clock::now();
     auto elapsed = current - start_time;
     return std::chrono::duration_cast<std::chrono::microseconds>(elapsed);
 }
diff --git a/src/core/host_timing.h b/src/core/host_timing.h
index a3a32e087..1d053a7fa 100644
--- a/src/core/host_timing.h
+++ b/src/core/host_timing.h
@@ -14,13 +14,15 @@
 #include <vector>
 
 #include "common/common_types.h"
+#include "common/spin_lock.h"
+#include "common/thread.h"
 #include "common/threadsafe_queue.h"
 
 namespace Core::HostTiming {
 
 /// A callback that may be scheduled for a particular core timing event.
 using TimedCallback = std::function<void(u64 userdata, s64 cycles_late)>;
-using sys_time_point = std::chrono::time_point<std::chrono::system_clock>;
+using sys_time_point = std::chrono::time_point<std::chrono::steady_clock>;
 
 /// Contains the characteristics of a particular event.
 struct EventType {
@@ -63,6 +65,23 @@ public:
     /// Tears down all timing related functionality.
     void Shutdown();
 
+    /// Pauses/Unpauses the execution of the timer thread.
+    void Pause(bool is_paused);
+
+    /// Pauses/Unpauses the execution of the timer thread and waits until paused.
+    void SyncPause(bool is_paused);
+
+    /// Checks if core timing is running.
+    bool IsRunning();
+
+    /// Checks if the timer thread has started.
+    bool HasStarted() {
+        return has_started;
+    }
+
+    /// Checks if there are any pending time events.
+    bool HasPendingEvents();
+
     /// Schedules an event in core timing
     void ScheduleEvent(s64 ns_into_future, const std::shared_ptr<EventType>& event_type,
                        u64 userdata = 0);
@@ -107,11 +126,14 @@ private:
     u64 event_fifo_id = 0;
 
     std::shared_ptr<EventType> ev_lost;
-    bool is_set = false;
-    std::condition_variable condvar;
-    std::mutex inner_mutex;
+    Common::Event event{};
+    Common::SpinLock basic_lock{};
     std::unique_ptr<std::thread> timer_thread;
+    std::atomic<bool> paused{};
+    std::atomic<bool> paused_set{};
+    std::atomic<bool> wait_set{};
     std::atomic<bool> shutting_down{};
+    std::atomic<bool> has_started{};
 };
 
 /// Creates a core timing event with the given name and callback.
diff --git a/src/tests/CMakeLists.txt b/src/tests/CMakeLists.txt
index 47ef30aa9..3f750b51c 100644
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -8,6 +8,7 @@ add_executable(tests
     core/arm/arm_test_common.cpp
     core/arm/arm_test_common.h
     core/core_timing.cpp
+    core/host_timing.cpp
     tests.cpp
 )
 
diff --git a/src/tests/core/host_timing.cpp b/src/tests/core/host_timing.cpp
new file mode 100644
index 000000000..ca9c8e50a
--- /dev/null
+++ b/src/tests/core/host_timing.cpp
@@ -0,0 +1,150 @@
+// Copyright 2016 Dolphin Emulator Project / 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <catch2/catch.hpp>
+
+#include <array>
+#include <bitset>
+#include <cstdlib>
+#include <memory>
+#include <string>
+
+#include "common/file_util.h"
+#include "core/core.h"
+#include "core/host_timing.h"
+
+// Numbers are chosen randomly to make sure the correct one is given.
+static constexpr std::array<u64, 5> CB_IDS{{42, 144, 93, 1026, UINT64_C(0xFFFF7FFFF7FFFF)}};
+static constexpr int MAX_SLICE_LENGTH = 10000; // Copied from CoreTiming internals
+static constexpr std::array<u64, 5> calls_order{{2,0,1,4,3}};
+static std::array<s64, 5> delays{};
+
+static std::bitset<CB_IDS.size()> callbacks_ran_flags;
+static u64 expected_callback = 0;
+static s64 lateness = 0;
+
+template <unsigned int IDX>
+void HostCallbackTemplate(u64 userdata, s64 nanoseconds_late) {
+    static_assert(IDX < CB_IDS.size(), "IDX out of range");
+    callbacks_ran_flags.set(IDX);
+    REQUIRE(CB_IDS[IDX] == userdata);
+    REQUIRE(CB_IDS[IDX] == CB_IDS[calls_order[expected_callback]]);
+    delays[IDX] = nanoseconds_late;
+    ++expected_callback;
+}
+
+static u64 callbacks_done = 0;
+
+struct ScopeInit final {
+    ScopeInit() {
+        core_timing.Initialize();
+    }
+    ~ScopeInit() {
+        core_timing.Shutdown();
+    }
+
+    Core::HostTiming::CoreTiming core_timing;
+};
+
+TEST_CASE("HostTiming[BasicOrder]", "[core]") {
+    ScopeInit guard;
+    auto& core_timing = guard.core_timing;
+    std::vector<std::shared_ptr<Core::HostTiming::EventType>> events;
+    events.resize(5);
+    events[0] =
+        Core::HostTiming::CreateEvent("callbackA", HostCallbackTemplate<0>);
+    events[1] =
+        Core::HostTiming::CreateEvent("callbackB", HostCallbackTemplate<1>);
+    events[2] =
+        Core::HostTiming::CreateEvent("callbackC", HostCallbackTemplate<2>);
+    events[3] =
+        Core::HostTiming::CreateEvent("callbackD", HostCallbackTemplate<3>);
+    events[4] =
+        Core::HostTiming::CreateEvent("callbackE", HostCallbackTemplate<4>);
+
+    expected_callback = 0;
+
+    core_timing.SyncPause(true);
+
+    u64 one_micro = 1000U;
+    for (std::size_t i = 0; i < events.size(); i++) {
+        u64 order = calls_order[i];
+        core_timing.ScheduleEvent(i*one_micro + 100U, events[order], CB_IDS[order]);
+    }
+    /// test pause
+    REQUIRE(callbacks_ran_flags.none());
+
+    core_timing.Pause(false); // No need to sync
+
+    while (core_timing.HasPendingEvents());
+
+    REQUIRE(callbacks_ran_flags.all());
+
+    for (std::size_t i = 0; i < delays.size(); i++) {
+        const double delay = static_cast<double>(delays[i]);
+        const double micro = delay / 1000.0f;
+        const double mili = micro / 1000.0f;
+        printf("HostTimer Pausing Delay[%zu]: %.3f %.6f\n", i, micro, mili);
+    }
+}
+
+#pragma optimize("", off)
+u64 TestTimerSpeed(Core::HostTiming::CoreTiming& core_timing) {
+    u64 start = core_timing.GetGlobalTimeNs().count();
+    u64 placebo = 0;
+    for (std::size_t i = 0; i < 1000; i++) {
+        placebo += core_timing.GetGlobalTimeNs().count();
+    }
+    u64 end = core_timing.GetGlobalTimeNs().count();
+    return (end - start);
+}
+#pragma optimize("", on)
+
+TEST_CASE("HostTiming[BasicOrderNoPausing]", "[core]") {
+    ScopeInit guard;
+    auto& core_timing = guard.core_timing;
+    std::vector<std::shared_ptr<Core::HostTiming::EventType>> events;
+    events.resize(5);
+    events[0] =
+        Core::HostTiming::CreateEvent("callbackA", HostCallbackTemplate<0>);
+    events[1] =
+        Core::HostTiming::CreateEvent("callbackB", HostCallbackTemplate<1>);
+    events[2] =
+        Core::HostTiming::CreateEvent("callbackC", HostCallbackTemplate<2>);
+    events[3] =
+        Core::HostTiming::CreateEvent("callbackD", HostCallbackTemplate<3>);
+    events[4] =
+        Core::HostTiming::CreateEvent("callbackE", HostCallbackTemplate<4>);
+
+    core_timing.SyncPause(true);
+    core_timing.SyncPause(false);
+
+    expected_callback = 0;
+
+    u64 start = core_timing.GetGlobalTimeNs().count();
+    u64 one_micro = 1000U;
+    for (std::size_t i = 0; i < events.size(); i++) {
+        u64 order = calls_order[i];
+        core_timing.ScheduleEvent(i*one_micro + 100U, events[order], CB_IDS[order]);
+    }
+    u64 end = core_timing.GetGlobalTimeNs().count();
+    const double scheduling_time = static_cast<double>(end - start);
+    const double timer_time = static_cast<double>(TestTimerSpeed(core_timing));
+
+    while (core_timing.HasPendingEvents());
+
+    REQUIRE(callbacks_ran_flags.all());
+
+    for (std::size_t i = 0; i < delays.size(); i++) {
+        const double delay = static_cast<double>(delays[i]);
+        const double micro = delay / 1000.0f;
+        const double mili = micro / 1000.0f;
+        printf("HostTimer No Pausing Delay[%zu]: %.3f %.6f\n", i, micro, mili);
+    }
+
+    const double micro = scheduling_time / 1000.0f;
+    const double mili = micro / 1000.0f;
+    printf("HostTimer No Pausing Scheduling Time: %.3f %.6f\n", micro, mili);
+    printf("HostTimer No Pausing Timer Time: %.3f %.6f\n", timer_time / 1000.f, timer_time / 1000000.f);
+}