Hi,
Can you post the source code for the java sample? I have a hard time
understanding how the sample can run so fast with java, here I get the
following results:
C#: 3.346 seconds
C (compiled with gcc O3, see attached source code): 1.132 seconds
Rolf
>Hi,
>
>I'm quite familiar with both the .NET and Java development environments,
but only recently have begun to experiment with mono, so forgive me if I'm
not clued-in.
>
>I specialize in numerical work that often involves a lot large-scale array
manipulation for linear algebra, timeseries, etc. My main production
platforms are OSX and Linux. I've been doing most of my work on the JVM
over the >past few years, though spent a couple of years with .NET when it
was pre-release / pre-1.0.
>
>My main interest is in Ocaml, particularly the F# variant as the basis for
my numerical work.
>
>One of the first things I do when considering a platform is run benchmarks,
as performance is critical for what I do. Starting with C# I wrote a test
to gauge the array-access overhead associated with the platform. Without
>knowing how to tweak the mono runtime to turn on any particular
optimisations, the results were quite poor for this specific test (see code
at the end of this posting).
>
>
>The test on my MacPro 2.6 Ghz / Snow Leopard with mono 2.6.1 gave the
result of:
>
> 16 sec, 130 ms for 1000 iterations
>
>the same code, modified just for IO, etc on the Java VM (without -server)
gave a runtime of:
>
> 0 sec, 831 ms
>
>changing the # of iterations to higher amounts did nothing to improve the
ratio. Java is 20x faster in this benchmark.
>
>I could not find any documentation concerning settings for the -optimize
flag on the mono VM, so perhaps there is a setting I should be using.
>
>Secondly, I saw the posting concerning the optional use of LLVM. I have
not been able to build mono on OSX as am having problems building glib. I'm
wondering whether anyone has a packaged up version of glib or better a
packaged up >version of mono with LLVM enabled.
>
>I have heard only good things about LLVM performance, so hoping that this
will help address this gap. Hopefully I am doing something wrong here and
the performance is much closer. Test code below ...
>
>regards
>
>Jonathan
--
http://tr8dr.wordpress.com/
#include <stdio.h>
#include <string.h>
double test1 (double *vec, int length)
{
double sum = 0;
int i, j;
for (i = 8; i < length; i++) {
vec [i] = 2 * vec [i] - vec [i-1];
for (j = 1; j < 8; j++)
sum += 1.3 * vec [j - 1];
}
return sum;
}
int main (int argc, char **argv)
{
const int iterations = 1000;
const int length = 100000;
double *vec = malloc (length * sizeof (double));
int i;
for (i = 0; i < length; i++) {
vec [i] = i;
}
double sum = 0;
for (i = 0; i < iterations; i++)
sum += test1 (vec, length);
printf ("result: %f\n", sum);
}_______________________________________________
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