Re: Why is Java so slow????

"Daniel Dyer" <"You don't need it">
Mon, 19 Nov 2007 19:57:00 -0000
On Mon, 19 Nov 2007 19:28:17 -0000, Java Performance Export =

<> wrote:

This "C" program takes about 11.5 seconds to print 50,000,000 lines or=

4.3 million lines / sec... output is to /dev/null

  Compiled with:
    gcc -O4 -o t t.c



#include <stdio.h>
int main(int argc, char ** argv)
  int lim = atoi(argv[1]);
  int i;
  for (i=1; i <= lim; i++)
    printf("this is line %d\n", i);


This Java class takes about 15.6 seconds to print 5,000,000 lines or
63,700 lines / sec ... 67 times slower!

======================= =

class t
    static public void main(String[] argv)
        int lim = new Integer(argv[0]);
        int i;
        for (i=0; i < lim; i++)
            System.out.println("This is line " + i);

======================= =

Try the Java printf so that you are at least comparing something similar=

(it should avoid a lot of the String allocations):

(java.lang.String, =


Also, try the -server switch on the JVM. It may well inline a lot of =

those method calls that you are seeing.

Finally, disregard your results until you have considered the following =

Java micro-benchmarking advice posted here by Chris Uppal a while back:



-- =

Daniel Dyer - Evolutionary Computation for Java

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