From 528b19a84287167d7699465e495b196d216b99db Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Sun, 5 Apr 2020 09:48:53 -0400
Subject: [PATCH] General: Tune the priority of main emulation threads so they
 have higher priority than less important helper threads.

---
 src/common/thread.cpp                         | 46 +++++++++++++++++++
 src/common/thread.h                           |  9 ++++
 src/core/core_timing.cpp                      |  1 +
 src/core/cpu_manager.cpp                      |  1 +
 src/video_core/gpu_thread.cpp                 |  1 +
 .../renderer_vulkan/vk_scheduler.cpp          |  2 +
 6 files changed, 60 insertions(+)

diff --git a/src/common/thread.cpp b/src/common/thread.cpp
index c9684aed93..33c8437f52 100644
--- a/src/common/thread.cpp
+++ b/src/common/thread.cpp
@@ -25,6 +25,52 @@
 
 namespace Common {
 
+#ifdef _WIN32
+
+void SetCurrentThreadPriority(ThreadPriority new_priority) {
+    auto handle = GetCurrentThread();
+    int windows_priority = 0;
+    switch (new_priority) {
+        case ThreadPriority::Low:
+            windows_priority = THREAD_PRIORITY_BELOW_NORMAL;
+            break;
+        case ThreadPriority::Normal:
+            windows_priority = THREAD_PRIORITY_NORMAL;
+            break;
+        case ThreadPriority::High:
+            windows_priority = THREAD_PRIORITY_ABOVE_NORMAL;
+            break;
+        case ThreadPriority::VeryHigh:
+            windows_priority = THREAD_PRIORITY_HIGHEST;
+            break;
+        default:
+            windows_priority = THREAD_PRIORITY_NORMAL;
+            break;
+    }
+    SetThreadPriority(handle, windows_priority);
+}
+
+#else
+
+void SetCurrentThreadPriority(ThreadPriority new_priority) {
+    pthread_t this_thread = pthread_self();
+
+    s32 max_prio = sched_get_priority_max(SCHED_OTHER);
+    s32 min_prio = sched_get_priority_min(SCHED_OTHER);
+    u32 level = static_cast<u32>(new_priority) + 1;
+
+    struct sched_param params;
+    if (max_prio > min_prio) {
+        params.sched_priority = min_prio + ((max_prio - min_prio) * level) / 4;
+    } else {
+        params.sched_priority = min_prio - ((min_prio - max_prio) * level) / 4;
+    }
+
+    pthread_setschedparam(this_thread, SCHED_OTHER, &params);
+}
+
+#endif
+
 #ifdef _MSC_VER
 
 // Sets the debugger-visible name of the current thread.
diff --git a/src/common/thread.h b/src/common/thread.h
index 127cc7e233..52b3594131 100644
--- a/src/common/thread.h
+++ b/src/common/thread.h
@@ -86,6 +86,15 @@ private:
     std::size_t generation = 0; // Incremented once each time the barrier is used
 };
 
+enum class ThreadPriority : u32 {
+    Low = 0,
+    Normal = 1,
+    High = 2,
+    VeryHigh = 3,
+};
+
+void SetCurrentThreadPriority(ThreadPriority new_priority);
+
 void SetCurrentThreadName(const char* name);
 
 } // namespace Common
diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp
index b02119494e..032b29e339 100644
--- a/src/core/core_timing.cpp
+++ b/src/core/core_timing.cpp
@@ -48,6 +48,7 @@ void CoreTiming::ThreadEntry(CoreTiming& instance) {
     std::string name = "yuzu:HostTiming";
     MicroProfileOnThreadCreate(name.c_str());
     Common::SetCurrentThreadName(name.c_str());
+    Common::SetCurrentThreadPriority(Common::ThreadPriority::VeryHigh);
     instance.on_thread_init();
     instance.ThreadLoop();
 }
diff --git a/src/core/cpu_manager.cpp b/src/core/cpu_manager.cpp
index 63c5788520..32afcf3ae9 100644
--- a/src/core/cpu_manager.cpp
+++ b/src/core/cpu_manager.cpp
@@ -337,6 +337,7 @@ void CpuManager::RunThread(std::size_t core) {
     }
     MicroProfileOnThreadCreate(name.c_str());
     Common::SetCurrentThreadName(name.c_str());
+    Common::SetCurrentThreadPriority(Common::ThreadPriority::High);
     auto& data = core_data[core];
     data.enter_barrier = std::make_unique<Common::Event>();
     data.exit_barrier = std::make_unique<Common::Event>();
diff --git a/src/video_core/gpu_thread.cpp b/src/video_core/gpu_thread.cpp
index 323185bfcd..738c6f0c1f 100644
--- a/src/video_core/gpu_thread.cpp
+++ b/src/video_core/gpu_thread.cpp
@@ -22,6 +22,7 @@ static void RunThread(Core::System& system, VideoCore::RendererBase& renderer,
     std::string name = "yuzu:GPU";
     MicroProfileOnThreadCreate(name.c_str());
     Common::SetCurrentThreadName(name.c_str());
+    Common::SetCurrentThreadPriority(Common::ThreadPriority::High);
     system.RegisterHostThread();
 
     // Wait for first GPU command before acquiring the window context
diff --git a/src/video_core/renderer_vulkan/vk_scheduler.cpp b/src/video_core/renderer_vulkan/vk_scheduler.cpp
index 82ec9180e5..56524e6f30 100644
--- a/src/video_core/renderer_vulkan/vk_scheduler.cpp
+++ b/src/video_core/renderer_vulkan/vk_scheduler.cpp
@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "common/microprofile.h"
+#include "common/thread.h"
 #include "video_core/renderer_vulkan/vk_device.h"
 #include "video_core/renderer_vulkan/vk_query_cache.h"
 #include "video_core/renderer_vulkan/vk_resource_manager.h"
@@ -133,6 +134,7 @@ void VKScheduler::BindGraphicsPipeline(VkPipeline pipeline) {
 }
 
 void VKScheduler::WorkerThread() {
+    Common::SetCurrentThreadPriority(Common::ThreadPriority::High);
     std::unique_lock lock{mutex};
     do {
         cv.wait(lock, [this] { return !chunk_queue.Empty() || quit; });