--- src/core/org/apache/jmeter/samplers/SampleResult.java	2008-03-12 13:02:10 +0000
+++ src/core/org/apache/jmeter/samplers/SampleResult.java	2008-03-23 12:55:47 +0000
@@ -26,6 +26,8 @@ 
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.lang.reflect.Method;
+import java.lang.reflect.InvocationTargetException;
 
 import org.apache.avalon.framework.configuration.Configuration;
 import org.apache.jmeter.assertions.AssertionResult;
@@ -140,6 +142,38 @@ 
 	private String dataEncoding;// (is this really the character set?) e.g.
 								// ISO-8895-1, UTF-8
 
+	private static Method initNanoTimeMethod() {
+		try {
+			return System.class.getMethod("nanoTime", null);
+		} catch (NoSuchMethodException e) {
+			return null;
+		}
+	}
+
+	private static boolean haveNanoTime() {
+		return nanoTimeMethod != null;
+	}
+
+	private static long nanoTime() {
+		Long result = null;
+		try {
+			result = (Long) nanoTimeMethod.invoke(null, null);
+		} catch (IllegalAccessException e) {
+			throw new RuntimeException(e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException(e);
+		}
+		return result.longValue();
+	}
+
+	private static final Method nanoTimeMethod = initNanoTimeMethod();
+
+	// a reference time from the nanosecond clock
+	private static final long referenceTimeNsClock = haveNanoTime() ? sampleNsClockInMs() : Long.MIN_VALUE;
+
+	private static final long referenceTimeMsClock = System.currentTimeMillis(); // a reference time from the
+																				 //  millisecond clock
+
 	private long time = 0; // elapsed time
 
 	private long latency = 0; // time to first response
@@ -228,7 +262,7 @@ 
 	 *            create the sample finishing now, else starting now
 	 */
 	protected SampleResult(long elapsed, boolean atend) {
-		long now = System.currentTimeMillis();
+		long now = currentTimeInMs();
 		if (atend) {
 			setTimes(now - elapsed, now);
 		} else {
@@ -262,7 +296,7 @@ 
 	 *            desired elapsed time
 	 */
 	public static SampleResult createTestSample(long elapsed) {
-		long now = System.currentTimeMillis();
+		long now = currentTimeInMs();
 		return createTestSample(now, now + elapsed);
 	}
 
@@ -280,6 +314,20 @@ 
 		stampAndTime(stamp, elapsed);
 	}
 
+	private static long sampleNsClockInMs() {
+		return nanoTime() / 1000000;
+	}
+
+	// Helper method to get 1 ms resolution timing.
+	public static long currentTimeInMs() {
+		if (haveNanoTime()) {
+			long elapsedInMs = sampleNsClockInMs() - referenceTimeNsClock;
+			return referenceTimeMsClock + elapsedInMs;
+		} else {
+			return System.currentTimeMillis();
+		}
+	}
+
 	// Helper method to maintain timestamp relationships
 	private void stampAndTime(long stamp, long elapsed) {
 		if (startTimeStamp) {
@@ -325,7 +373,7 @@ 
 		if (startTime != 0 || endTime != 0){
 			throw new RuntimeException("Calling setTime() after start/end times have been set");
 		}
-		long now = System.currentTimeMillis();
+		long now = currentTimeInMs();
 	    setTimes(now - elapsed, now);
 	}
 
@@ -805,7 +853,7 @@ 
 	 */
 	public void sampleStart() {
 		if (startTime == 0) {
-			setStartTime(System.currentTimeMillis());
+			setStartTime(currentTimeInMs());
 		} else {
 			log.error("sampleStart called twice", new Throwable("Invalid call sequence"));
 		}
@@ -817,7 +865,7 @@ 
 	 */
 	public void sampleEnd() {
 		if (endTime == 0) {
-			setEndTime(System.currentTimeMillis());
+			setEndTime(currentTimeInMs());
 		} else {
 			log.error("sampleEnd called twice", new Throwable("Invalid call sequence"));
 		}
@@ -831,7 +879,7 @@ 
 		if (pauseTime != 0) {
 			log.error("samplePause called twice", new Throwable("Invalid call sequence"));
 		}
-		pauseTime = System.currentTimeMillis();
+		pauseTime = currentTimeInMs();
 	}
 
 	/**
@@ -842,7 +890,7 @@ 
 		if (pauseTime == 0) {
 			log.error("sampleResume without samplePause", new Throwable("Invalid call sequence"));
 		}
-		idleTime += System.currentTimeMillis() - pauseTime;
+		idleTime += currentTimeInMs() - pauseTime;
 		pauseTime = 0;
 	}
 
@@ -943,7 +991,7 @@ 
      *
      */
 	public void latencyEnd() {
-		latency = System.currentTimeMillis() - startTime - idleTime;
+		latency = currentTimeInMs() - startTime - idleTime;
 	}
 
 	/**
--- test/src/org/apache/jmeter/samplers/TestSampleResult.java	2008-03-12 13:02:10 +0000
+++ test/src/org/apache/jmeter/samplers/TestSampleResult.java	2008-03-23 12:59:52 +0000
@@ -98,6 +98,10 @@ 
             assertEquals("sample of size 100 bytes", res.getSampleLabel());
         }
 
+        private static long sampleClock() {
+            return SampleResult.currentTimeInMs();
+        }
+
         public void testSubResults() throws Exception {
         	// This test tries to emulate a http sample, with two
         	// subsamples, representing images that are downloaded for the
@@ -106,8 +110,8 @@ 
             // Sample that will get two sub results, simulates a web page load 
             SampleResult resWithSubResults = new SampleResult();            
 
-            long beginTest = System.currentTimeMillis();
-            
+            long beginTest = sampleClock();
+
             resWithSubResults.sampleStart();
             Thread.sleep(100);
             resWithSubResults.setBytes(300);
@@ -142,8 +146,8 @@ 
             resNoSubResults2.sampleEnd();
             long sample2Time = resNoSubResults2.getTime();
 
-            long overallTime = System.currentTimeMillis() - beginTest;
-            
+            long overallTime = sampleClock() - beginTest;
+
             assertTrue(resNoSubResults2.isSuccessful());
             assertEquals(200, resNoSubResults2.getBytes());
             assertEquals("sample with no subresults", resNoSubResults2.getSampleLabel());