Xiao-Feng Li wrote:
> A quick check shows that lots of time is spent in sqrt() computation:
>
> hyluni.dll!___ieee754_sqrt() + 0x1f3 C
> hyluni.dll!_fdlibm_sqrt() + 0x11 C
> hyluni.dll!internal_sqrt(double arg1=1528.7960683139602) Line 301 +
> 0xe C
> hyluni.dll!Java_java_lang_Math_sqrt(const JNINativeInterface_ * *
> env=0x0206aaa0, _jobject * jclazz=0x0013f5b0, double
> arg1=1528.7960683139602) Line 596 + 0xe C
> 0345c1b2()
In this micro-bench ...
======================================================================
public static void main(String[] args) {
// warm-up
double result = 0.0d;
for (int i = 0; i < 10000; i++) {
result += Math.sqrt((double) i);
}
// Timed run
result = 0.0d;
long start = System.currentTimeMillis();
for (int i = 0; i < 1000000; i++) {
result += Math.sqrt((double) i);
}
System.out.println("Result = " + result + " in "
+ (System.currentTimeMillis() - start) + "ms");
}
======================================================================
Harmony 5.0 M3 prints
Result = 6.666661664588418E8 in 1352ms
IBM 5.0 SR5a prints
Result = 6.666661664588418E8 in 40ms
Sun 1.6.0-b105 prints
Result = 6.666661664588418E8 in 40ms
Can we squeeze a bit more out of the JIT?
Regards,
Tim
