Code optimizations in RATE_LIMITER and throughput test

src/org/jgroups/protocols/RATE_LIMITER.java

@@ -22,12 +22,12 @@ public class RATE_LIMITER extends Protocol {
 
     @Property(description="Max number of bytes to be sent in time_period ms. Blocks the sender if exceeded until a new " +
             "time period has started")
-    protected long max_bytes=500000;
+    protected long max_bytes=300000;
 
     @Property(description="Number of milliseconds during which max_bytes bytes can be sent")
-    protected long time_period=1000L;
+    protected long time_period=10L;
 
-    protected long time_period_ns=TimeUnit.NANOSECONDS.convert(time_period, TimeUnit.MILLISECONDS);
+    protected long time_period_ns;
 
 
     /** Keeps track of the number of bytes sent in the current time period */
@@ -86,6 +86,7 @@ public void init() throws Exception {
         super.init();
         if(time_period <= 0)
             throw new IllegalArgumentException("time_period needs to be positive");
+        time_period_ns=TimeUnit.NANOSECONDS.convert(time_period, TimeUnit.MILLISECONDS);
     }
 
     public void start() throws Exception {
@@ -115,25 +116,17 @@ public Object down(Event evt) {
                     max_bytes=len;
                 }
 
-                while(running) {
+                if(num_bytes_sent_in_period + len > max_bytes) { // size exceeded
                     long current_time=System.nanoTime();
-                    boolean size_exceeded=num_bytes_sent_in_period + len > max_bytes,
-                            time_exceeded=current_time >= end_of_current_period;
-                    if(!size_exceeded && !time_exceeded)
-                        break;
-
-                    if(time_exceeded) {
-                        num_bytes_sent_in_period=0L;
-                        end_of_current_period=current_time + time_period_ns;
-                    }
-                    else { // size exceeded
-                        long block_time=current_time - end_of_current_period;
-                        if(block_time > 0) {
-                            LockSupport.parkNanos(block_time);
-                            num_blockings++;
-                            total_block_time+=block_time;
-                        }
+                    if(current_time < end_of_current_period) {
+                        long block_time=end_of_current_period - current_time;
+                        LockSupport.parkNanos(block_time);
+                        num_blockings++;
+                        total_block_time+=block_time;
+                        current_time=end_of_current_period; // more or less, avoid having to call nanoTime() again
                     }
+                    end_of_current_period=current_time + time_period_ns; // start a new time period
+                    num_bytes_sent_in_period=0;
                 }
             }
             finally {

tests/junit-functional/org/jgroups/protocols/RATE_LIMITER_Test.java

@@ -14,7 +14,6 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.LockSupport;
 
 
@@ -26,7 +25,7 @@
 public class RATE_LIMITER_Test {
 
     public void testThroughput() throws Exception {
-        byte[] buffer=new byte[1];
+        byte[] buffer=new byte[1000];
         RATE_LIMITER limiter=create(10, 100000);
         long target_throughput=10000000; // 10MB/s
         final CountDownLatch latch=new CountDownLatch(1);
@@ -58,9 +57,9 @@ public void testThroughput() throws Exception {
 
         // 50% deviation below is ok: e.g. max_bytes=100000, and sending 50001 bytes !
         // In the real setup, there a warning if the system is not configured for max_bytes to be a multiple of frag_size
-        long min_value=(long)(target_throughput * 0.45);
+        long min_value=(long)(target_throughput * 0.45), max_value=(long)(target_throughput * 1.1);
         for(long value: list) {
-            assert value >= min_value && value <= target_throughput;
+            assert value >= min_value && value <= max_value;
         }
     }