[armedbear-devel] Some Array vs GETFILED access times - armedbear-devel - mailman3.common-lisp.net

2 Nov 2009


      ABCL,
  For implementing MOP-like objects these times are something to consider.
What I draw from it is when not messing with arrays (array bounds checking).
   Every case is better than.
JVM-L,
   Do these tests with times make sense?
package ArrayTests;
public class ArrayVsClass {
public static void main(String[] args) {
  long lVectorStartTime = System.currentTimeMillis();
  int iterations = Integer.MAX_VALUE;
  while (iterations-- > 0) {
  // int iterations2 = 10;
   //while (iterations2-- > 0)
   {
       //testArray(); // ARRAY
    // vs
    //testGETFIELD(); // GETFIELD
    // vs
    testIBean(); // INVOKE INTERFACE
    // vs
    //testBean(); // INVOKE VIRTUAL
    // vs
    //testABean(); // INVOKE VIRTUAL POSSIBLY THROW 
    // vs
    //testSlots(); // INVOKE FOR AVALUE 
   }
  }
  long lVectorRunTime = System.currentTimeMillis() - lVectorStartTime;
  System.out.println("Bench time: " + lVectorRunTime);
}
// SLOTS time: 33157,33250,33156
 public static void testSlots() {
  ClassWithSlots oneSlot = new ClassWithSlots(6);
int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += oneSlot.getValue();
  }
 }
// Array time: 18438,18437,18422
 public static void testArray() {
  final long[] accessArray = new long[] { 6 };
  int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += accessArray[0];
  }
 }
// GETFIELD time: 14688,14531,14453
 public static void testGETFIELD() {
  ClassWithOneSlot oneSlot = new ClassWithOneSlot(6);
int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += oneSlot.slot;
  }
 }
// INVOKE VIRTUAL time: 14750,14594,14719
 public static void testBean() {
  ClassWithOneSlot oneSlot = new ClassWithOneSlot(6);
int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += oneSlot.getValue();
  }
 }
// INVOKE INTERFACE time: 14469,14610,14859
 public static void testIBean() {
  IBeanWithOneSlot oneSlot = new ClassWithOneSlot(6);
int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += oneSlot.getValue();
  }
 }
// INVOKE VIRTUAL POSSIBLY THROW time: 14641,14594,14547
 public static void testABean() {
  AClassWithOneSlot oneSlot = new ClassWithOneSlot(6);
int iterations = Integer.MAX_VALUE;
  long result = 0;
  while (iterations-- > 0) {
   result += oneSlot.getValue();
  }
 }
static interface IBeanWithOneSlot {
  public long getValue();
 }
static class ClassWithOneSlot extends AClassWithOneSlot implements IBeanWithOneSlot {
  final public long slot;
ClassWithOneSlot(long s) {
   slot = s;
  }
@Override
  final public long getValue() {
   return slot;
  }
 }
static class ClassWithSlots  {
  final public long[] slots = new long[1];
ClassWithSlots(long s) {
   slots[0] = s;
  }
final public long getValue() {
   return slots[0];
  }
 }
static abstract class AClassWithOneSlot implements IBeanWithOneSlot {
@Override
  public long getValue() {
   throw new NullPointerException();
  }
}
}