I'm writing a processing intensive digital sound processing app
(requires numerous (50,000) Fast Fourier Transforms - FFT). This
challenge led me to perform basic performance tests of Android running
on an HTC Hero.
The results show the Dalvik VM to be >20 times slower than a modern
JIT-enabled JVM running J2ME and 25-50 times slower than a C program
performing the same operations on a similarly powered mobile phone.
For example, this simple iteration over an empty method 2 million
times takes 1.4 seconds even though it doesn’t do anything. The same
iteration is performed in milliseconds by a C program and about 100ms
on a modern JVM
public void performanceTest1() {
for (int i = 0; i < 2000000; i++) {
emptyMethod();
}
}
private int emptyMethod() {
return 0;
}
Doing something a little more complex like calculating the imaginary
component of a complex conjugate 2 million times takes 3.2 seconds.
Again, this takes milliseconds on other mobile phones running J2ME or
C.
public void performanceTest2() {
for (int i = 0; i < 2000000; i++) {
int a = 5;
int b = 5;
int c = 5;
int x = 5;
int y = 5;
y = ((a >> 16) * ((c << 16) >> 16)) + (((a & 0X0000FFFF) * ((c
<<
16) >> 16)) >> 16);
y = -y;
y += ((b >> 16) * (c >> 16)) + (((b & 0X0000FFFF) * (c >> 16))
>>
16);
}
}
Has anyone else been able to overcome these performance issues of
Android?
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