Add support for using the current thread id.

peter-lawrey · peter-lawrey · commit 13dcd5de8223 · 2013-12-25T08:35:58.000Z
diff --git a/affinity/src/main/java/net/openhft/affinity/AffinitySupport.java b/affinity/src/main/java/net/openhft/affinity/AffinitySupport.java
@@ -21,6 +21,7 @@
 import net.openhft.affinity.impl.WindowsJNAAffinity;
 import org.jetbrains.annotations.NotNull;
 
+import java.lang.reflect.Field;
 import java.util.logging.Logger;
 
 /**
@@ -61,6 +62,10 @@ public static int getCpu() {
         return AFFINITY_IMPL.getCpu();
     }
 
+    public static int getThreadId() {
+        return AFFINITY_IMPL.getThreadId();
+    }
+
     public static boolean isJNAAvailable() {
         if (JNAAvailable == null)
             try {
@@ -71,4 +76,17 @@ public static boolean isJNAAvailable() {
             }
         return JNAAvailable;
     }
+
+    public static void setThreadId() {
+        try {
+            int threadId = getThreadId();
+            final Field tid = Thread.class.getDeclaredField("tid");
+            tid.setAccessible(true);
+            final Thread thread = Thread.currentThread();
+            tid.setLong(thread, threadId);
+            Logger.getAnonymousLogger().info("Set " + thread.getName() + " to thread id " + threadId);
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
+    }
 }
diff --git a/affinity/src/main/java/net/openhft/affinity/impl/PosixJNAAffinity.java b/affinity/src/main/java/net/openhft/affinity/impl/PosixJNAAffinity.java
@@ -102,16 +102,62 @@ public int getCpu() {
         }
     }
 
+    private static final int PROCESS_ID;
+
     @Override
     public int getProcessId() {
-        return CLibrary.INSTANCE.getpid();
+        return PROCESS_ID;
+    }
+
+    static {
+        int processId;
+        try {
+            processId = CLibrary.INSTANCE.getpid();
+        } catch (Exception ignored) {
+            processId = -1;
+        }
+        PROCESS_ID = processId;
     }
 
+    private final ThreadLocal<Integer> THREAD_ID = new ThreadLocal<Integer>();
+
     @Override
     public int getThreadId() {
+        if (ISLINUX) {
+            Integer tid = THREAD_ID.get();
+            if (tid == null)
+                THREAD_ID.set(tid = CLibrary.INSTANCE.syscall(SYS_gettid, NO_ARGS));
+            return tid;
+        }
         return -1;
     }
 
+    private static final boolean ISLINUX = "Linux".equals(System.getProperty("os.name"));
+
+    private static final boolean IS64BIT = is64Bit0();
+
+    private static final int SYS_gettid = is64Bit() ? 186 : 224;
+
+    private static final Object[] NO_ARGS = {};
+
+    public static boolean is64Bit() {
+        return IS64BIT;
+    }
+
+    private static boolean is64Bit0() {
+        String systemProp;
+        systemProp = System.getProperty("com.ibm.vm.bitmode");
+        if (systemProp != null) {
+            return "64".equals(systemProp);
+        }
+        systemProp = System.getProperty("sun.arch.data.model");
+        if (systemProp != null) {
+            return "64".equals(systemProp);
+        }
+        systemProp = System.getProperty("java.vm.version");
+        return systemProp != null && systemProp.contains("_64");
+    }
+
 
     /**
      * @author BegemoT
@@ -131,6 +177,8 @@ int sched_getaffinity(final int pid,
         int sched_getcpu() throws LastErrorException;
 
         int getpid() throws LastErrorException;
+
+        int syscall(int number, Object... args) throws LastErrorException;
     }
 
     static {
diff --git a/affinity/src/test/java/net/openhft/affinity/impl/PosixJNAAffinityTest.java b/affinity/src/test/java/net/openhft/affinity/impl/PosixJNAAffinityTest.java
@@ -16,9 +16,13 @@
 
 package net.openhft.affinity.impl;
 
+import net.openhft.affinity.AffinitySupport;
 import net.openhft.affinity.IAffinity;
 import org.junit.Assume;
 import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
 
 /**
  * @author peter.lawrey
@@ -33,4 +37,25 @@ public static void checkJniLibraryPresent() {
     public IAffinity getImpl() {
         return PosixJNAAffinity.INSTANCE;
     }
+
+    @Test
+    public void testGettid() {
+        System.out.println("pid=" + PosixJNAAffinity.INSTANCE.getProcessId());
+        System.out.println("tid=" + PosixJNAAffinity.INSTANCE.getThreadId());
+        AffinitySupport.setThreadId();
+
+        for (int j = 0; j < 10; j++) {
+            final int runs = 5000;
+            long tid = 0;
+            long time = 0;
+            for (int i = 0; i < runs; i++) {
+                long start = System.nanoTime();
+                tid = Thread.currentThread().getId();
+                time += System.nanoTime() - start;
+                assertTrue(tid > 0);
+                assertTrue(tid < 1 << 16);
+            }
+            System.out.printf("gettid took an average of %,d ns, tid=%d%n", time / runs, tid);
+        }
+    }
 }
