Re: [GNU Crypto] performance issues

[Raif S. Naffah]

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version #2:

- ----- begin Performance.java -----
public class Performance {

   private static final int ROUNDS = 100000;
   private static int R;
   private static long T1 = 0;
   private static long T2 = 0;

   // default constructor

   public static final void main(String[] args) {
      Performance instance = new Performance();

      instance.test1();
      instance.test2();
   }

   /** comparing System.arraycopy to plain for loop. */
   private void test1() {
      byte[] dst = new byte[256];
      byte[] src = new byte[256];
      for (R = 0; R < 256; R++) {
         src[R] = (byte) R;
      }
      T1 = -System.currentTimeMillis();
      for (R = 0; R < ROUNDS; R++) {
         for (int j = 0; j < 256; j++) {
            dst[j] = src[j];
         }
      }
      T1 += System.currentTimeMillis();

      T2 = -System.currentTimeMillis();
      for (R = 0; R < ROUNDS; R++) {
         System.arraycopy(src, 0, dst, 0, 256);
      }
      T2 += System.currentTimeMillis();

      System.out.println("*** Test #1: System.arraycopy / for loop");
      System.out.println("    for loop: "+T1);
      System.out.println("   arraycopy: "+T2);
   }

   /** comparing widening references. */
   private void test2() {
      byte[] dst = new byte[256];
      byte[] srcBytes = new byte[256];
      int[] srcInts = new int[256];
      for (R = 0; R < 256; R++) {
         srcBytes[R] = (byte) R;
         srcInts[R] = R;
      }
      byte b = 0;

      T1 = -System.currentTimeMillis();
      for (R = 0; R < ROUNDS; R++) {
         for (int j = 0; j < 256; j++) {
            b = (byte)((srcBytes[j] & 0xFF) ^ (srcBytes[b & 0xFF] & 
0xFF));
            srcBytes[j] = b;
         }
      }
      T1 += System.currentTimeMillis();

      int t = 0;
      T2 = -System.currentTimeMillis();
      for (R = 0; R < ROUNDS; R++) {
         for (int j = 0; j < 256; j++) {
            t = srcBytes[j] ^ srcInts[t & 0xFF];
            srcBytes[j] = (byte) t;
         }
      }
      T2 += System.currentTimeMillis();

      System.out.println("*** Test #2: Widening references");
      System.out.println("   bytes only: "+T1);
      System.out.println("   bytes+ints: "+T2);
   }
}
- ----- end Performance.java -----
- ----- begin runit -----
#!/bin/sh

jikes -classpath /usr/java/jdk1.3.1_05/jre/lib/rt.jar:. \
 -d classes src/Performance.java
echo "jikes+java..."
java -classpath classes Performance
echo

echo "jikes+gij..."
cd classes; gij Performance; cd ..
echo

gcj --main=Performance -o Performance src/Performance.java
echo "gcj (deault)..."
./Performance
echo

gcj -march=athlon-xp -O3 -fno-bounds-check \
 --main=Performance -o Performance src/Performance.java
echo "gcj -march -O3 -fno-bounds-check..."
./Performance
echo
- ----- end runit -----

address@hidden perf]$ ./runit
jikes+java...
*** Test #1: System.arraycopy / for loop
    for loop: 356
   arraycopy: 25
*** Test #2: Widening references
   bytes only: 312
   bytes+ints: 234

jikes+gij...
*** Test #1: System.arraycopy / for loop
    for loop: 4832
   arraycopy: 64
*** Test #2: Widening references
   bytes only: 10538
   bytes+ints: 8908

gcj (deault)...
*** Test #1: System.arraycopy / for loop
    for loop: 413
   arraycopy: 18
*** Test #2: Widening references
   bytes only: 750
   bytes+ints: 611

gcj -march -O3 -fno-bounds-check...
*** Test #1: System.arraycopy / for loop
    for loop: 53
   arraycopy: 18
*** Test #2: Widening references
   bytes only: 113
   bytes+ints: 120


cheers;
rsn
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