From a2d29412cbda3e0dc57c49c5d4c098e8ba73cbb5 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Sat, 27 Nov 2021 20:31:46 +0100
Subject: [PATCH] Core/Common: Corrections to core timing and add critical
 priority.

---
 src/common/thread.cpp    | 13 +++++++++----
 src/common/thread.h      |  1 +
 src/core/core_timing.cpp |  2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/common/thread.cpp b/src/common/thread.cpp
index f932a72909..924f0df1b3 100644
--- a/src/common/thread.cpp
+++ b/src/common/thread.cpp
@@ -47,6 +47,9 @@ void SetCurrentThreadPriority(ThreadPriority new_priority) {
     case ThreadPriority::VeryHigh:
         windows_priority = THREAD_PRIORITY_HIGHEST;
         break;
+    case ThreadPriority::Critical:
+        windows_priority = THREAD_PRIORITY_TIME_CRITICAL;
+        break;
     default:
         windows_priority = THREAD_PRIORITY_NORMAL;
         break;
@@ -59,9 +62,11 @@ void SetCurrentThreadPriority(ThreadPriority new_priority) {
 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;
+    const auto scheduling_type =
+        new_priority != ThreadPriority::Critical ? SCHED_OTHER : SCHED_FIFO;
+    s32 max_prio = sched_get_priority_max(scheduling_type);
+    s32 min_prio = sched_get_priority_min(scheduling_type);
+    u32 level = std::max(static_cast<u32>(new_priority) + 1, 4U);
 
     struct sched_param params;
     if (max_prio > min_prio) {
@@ -70,7 +75,7 @@ void SetCurrentThreadPriority(ThreadPriority new_priority) {
         params.sched_priority = min_prio - ((min_prio - max_prio) * level) / 4;
     }
 
-    pthread_setschedparam(this_thread, SCHED_OTHER, &params);
+    pthread_setschedparam(this_thread, scheduling_type, &params);
 }
 
 #endif
diff --git a/src/common/thread.h b/src/common/thread.h
index a631225162..1552f58e0f 100644
--- a/src/common/thread.h
+++ b/src/common/thread.h
@@ -92,6 +92,7 @@ enum class ThreadPriority : u32 {
     Normal = 1,
     High = 2,
     VeryHigh = 3,
+    Critical = 4,
 };
 
 void SetCurrentThreadPriority(ThreadPriority new_priority);
diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp
index 9185029290..b6c295ada6 100644
--- a/src/core/core_timing.cpp
+++ b/src/core/core_timing.cpp
@@ -46,7 +46,7 @@ void CoreTiming::ThreadEntry(CoreTiming& instance) {
     constexpr char name[] = "yuzu:HostTiming";
     MicroProfileOnThreadCreate(name);
     Common::SetCurrentThreadName(name);
-    Common::SetCurrentThreadPriority(Common::ThreadPriority::VeryHigh);
+    Common::SetCurrentThreadPriority(Common::ThreadPriority::Critical);
     instance.on_thread_init();
     instance.ThreadLoop();
     MicroProfileOnThreadExit();