Add NativeAccessor#setAffinity

Author: acrylic-style

CMakeLists.txt

@@ -6,6 +6,14 @@ set(JAVA_AWT_LIBRARY "")
 set(JAVA_AWT_INCLUDE_PATH "")
 find_package(JNI)
 
+find_package(Threads REQUIRED)
+if(THREADS_HAVE_PTHREAD_ARG)
+  target_compile_options(nativeutil PUBLIC "-pthread")
+endif()
+if(CMAKE_THREAD_LIBS_INIT)
+  target_link_libraries(nativeutil "${CMAKE_THREAD_LIBS_INIT}")
+endif()
+
 include_directories(.)
 if (JNI_FOUND)
     include_directories("${JNI_INCLUDE_DIRS}")

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>net.blueberrymc</groupId>
     <artifactId>native-util</artifactId>
-    <version>2.1.2</version>
+    <version>2.2.0-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>native-util</name>

src/main/c/native_util.cpp

@@ -2,6 +2,10 @@
 #include "common_tools.cpp"
 #include <cstring>
 #include <string>
+#include <jni.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdio.h>
 
 #pragma ide diagnostic ignored "OCUnusedGlobalDeclarationInspection"
 
@@ -812,4 +816,19 @@ JNIEXPORT jlong JNICALL Java_net_blueberrymc_nativeutil_NativeAccessor_memset
     return addr_to_java(memset(addr_from_java(address), value, size));
 }
 
+JNIEXPORT void JNICALL Java_net_blueberrymc_nativeutil_NativeAccessor_setAffinity
+        (JNIEnv *, jclass, jint threadId, jint cpuId) {
+    #if !__APPLE__
+    cpu_set_t cpuset;
+    CPU_ZERO(&cpuset);
+    CPU_SET(cpuId, &cpuset);
+
+    pthread_t thread = (pthread_t) threadId;
+    int result = pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
+    if (result != 0) {
+        perror("pthread_setaffinity_np failed");
+    }
+    #endif
+}
+
 }

src/main/c/native_util.h

@@ -553,6 +553,9 @@ JNIEXPORT void JNICALL Java_net_blueberrymc_nativeutil_NativeAccessor_free
 JNIEXPORT jlong JNICALL Java_net_blueberrymc_nativeutil_NativeAccessor_memset
         (JNIEnv *, jclass, jlong, jint, jint);
 
+JNIEXPORT void JNICALL Java_net_blueberrymc_nativeutil_NativeAccessor_setAffinity
+        (JNIEnv *, jclass, jint, jint);
+
 #ifdef __cplusplus
 }
 #endif

src/main/java/net/blueberrymc/nativeutil/NativeAccessor.java

@@ -182,4 +182,6 @@ public class NativeAccessor {
 
     @NativeType("void *")
     public static native long memset(@NativeType("void *") long address, @NativeType("int") int value, @NativeType("size_t") int size);
+
+    public static native void setAffinity(int threadId, int cpuId);
 }

src/main/java/net/blueberrymc/nativeutil/NativeUtil.java

@@ -1126,4 +1126,13 @@ public static void free(long address) {
     public static long memset(long address, int value, int size) {
         return NativeAccessor.memset(address, value, size);
     }
+
+    /**
+     * Sets the CPU affinity of the specified thread. This method only works on Linux.
+     * @param threadId the thread id
+     * @param cpuId the cpu id
+     */
+    public static void setAffinity(int threadId, int cpuId) {
+        NativeAccessor.setAffinity(threadId, cpuId);
+    }
 }