Feat[affinity]: added a way to force the MC rendering thread to run only on the highest-clocked core

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/prefs/LauncherPreferences.java

@@ -58,6 +58,7 @@ public class LauncherPreferences {
     public static boolean PREF_BUTTON_ALL_CAPS = true;
     public static boolean PREF_DUMP_SHADERS = false;
     public static float PREF_DEADZONE_SCALE = 1f;
+    public static boolean PREF_BIG_CORE_AFFINITY = false;
 
 
     public static void loadPreferences(Context ctx) {
@@ -98,6 +99,7 @@ public class LauncherPreferences {
         PREF_BUTTON_ALL_CAPS = DEFAULT_PREF.getBoolean("buttonAllCaps", true);
         PREF_DUMP_SHADERS = DEFAULT_PREF.getBoolean("dump_shaders", false);
         PREF_DEADZONE_SCALE = DEFAULT_PREF.getInt("gamepad_deadzone_scale", 100)/100f;
+        PREF_BIG_CORE_AFFINITY = DEFAULT_PREF.getBoolean("bigCoreAffinity", false);
 
         String argLwjglLibname = "-Dorg.lwjgl.opengl.libname=";
         for (String arg : JREUtils.parseJavaArguments(PREF_CUSTOM_JAVA_ARGS)) {

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/utils/JREUtils.java

@@ -218,6 +218,7 @@ public class JREUtils {
                 envMap.put("POJAVEXEC_EGL","libEGL_angle.so"); // Use ANGLE EGL
             }
         }
+        if(LauncherPreferences.PREF_BIG_CORE_AFFINITY) envMap.put("POJAV_BIG_CORE_AFFINITY", "1");
         envMap.put("AWTSTUB_WIDTH", Integer.toString(CallbackBridge.windowWidth > 0 ? CallbackBridge.windowWidth : CallbackBridge.physicalWidth));
         envMap.put("AWTSTUB_HEIGHT", Integer.toString(CallbackBridge.windowHeight > 0 ? CallbackBridge.windowHeight : CallbackBridge.physicalHeight));
 

app_pojavlauncher/src/main/jni/Android.mk

@@ -43,6 +43,7 @@ LOCAL_MODULE := pojavexec
 # LOCAL_CFLAGS += -DDEBUG
 # -DGLES_TEST
 LOCAL_SRC_FILES := \
+    bigcoreaffinity.c \
     egl_bridge.c \
     ctxbridges/gl_bridge.c \
     ctxbridges/egl_loader.c \

app_pojavlauncher/src/main/jni/bigcoreaffinity.c

@@ -0,0 +1,55 @@
+//
+// Created by maks on 19.06.2023.
+//
+
+#define _GNU_SOURCE // we are GNU GPLv3
+
+#include <linux/limits.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <string.h>
+
+#define FREQ_MAX 256
+void bigcore_format_cpu_path(char* buffer, unsigned int cpu_core) {
+    snprintf(buffer, PATH_MAX, "/sys/devices/system/cpu/cpu%i/cpufreq/cpuinfo_max_freq", cpu_core);
+}
+
+void bigcore_set_affinity() {
+    char path_buffer[PATH_MAX];
+    char freq_buffer[FREQ_MAX];
+    char* discard;
+    unsigned long core_freq;
+    unsigned long max_freq = 0;
+    unsigned int corecnt = 0;
+    unsigned int big_core_id = 0;
+    while(1) {
+        bigcore_format_cpu_path(path_buffer, corecnt);
+        int corefreqfd = open(path_buffer, O_RDONLY);
+        if(corefreqfd != -1) {
+            ssize_t read_count = read(corefreqfd, freq_buffer, FREQ_MAX);
+            close(corefreqfd);
+            freq_buffer[read_count] = 0;
+            core_freq = strtoul(freq_buffer, &discard, 10);
+            if(core_freq >= max_freq) {
+                max_freq = core_freq;
+                big_core_id = corecnt;
+            }
+        }else{
+            break;
+        }
+        corecnt++;
+    }
+    printf("bigcore: big CPU number is %u, frequency %lu Hz\n", big_core_id, max_freq);
+    cpu_set_t bigcore_affinity_set;
+    CPU_ZERO(&bigcore_affinity_set);
+    CPU_SET_S(big_core_id, CPU_SETSIZE, &bigcore_affinity_set);
+    int result = sched_setaffinity(0, CPU_SETSIZE, &bigcore_affinity_set);
+    if(result != 0) {
+        printf("bigcore: setting affinity failed: %s\n", strerror(result));
+    }else{
+        printf("bigcore: forced current thread onto big core\n");
+    }
+}

app_pojavlauncher/src/main/jni/egl_bridge.c

@@ -598,6 +598,7 @@ struct PotatoBridge potatoBridge;
 #include "ctxbridges/osmesa_loader.h"
 int (*vtest_main_p) (int argc, char** argv);
 void (*vtest_swap_buffers_p) (void);
+void bigcore_set_affinity();
 
 #define RENDERER_GL4ES 1
 #define RENDERER_VK_ZINK 2
@@ -926,6 +927,7 @@ void* egl_make_current(void* window) {
 
 bool locked = false;
 void pojavMakeCurrent(void* window) {
+    if(getenv("POJAV_BIG_CORE_AFFINITY") != NULL) bigcore_set_affinity();
     //if(OSMesaGetCurrentContext_p() != NULL) {
     //    printf("OSMDroid: skipped context reset\n");
     //    return JNI_TRUE;

app_pojavlauncher/src/main/res/values/strings.xml

@@ -370,4 +370,6 @@
     <string name="preference_wipe_controller_description">Allow you to remap the controller buttons</string>
     <string name="preference_deadzone_scale_title">Joystick deadzone scale</string>
     <string name="preference_deadzone_scale_description">Increase it if the joystick drifts</string>
+    <string name="preference_force_big_core_title">Force renderer to run on the big core</string>
+    <string name="preference_force_big_core_desc">Forces the Minecraft render thread to run on the core with the highest max frequency</string>
 </resources>

app_pojavlauncher/src/main/res/xml/pref_experimental.xml

@@ -9,6 +9,11 @@
             android:title="@string/preference_shader_dump_title"
             android:summary="@string/preference_shader_dump_description"
             />
+        <SwitchPreference
+            android:defaultValue="false"
+            android:key="bigCoreAffinity"
+            android:title="@string/preference_force_big_core_title"
+            android:summary="@string/preference_force_big_core_desc" />
 
     </PreferenceCategory>
 </PreferenceScreen>