On 3/30/17 1:03 PM, Ervin Bosenbacher wrote:
On Thursday, 30 March 2017 at 10:28:01 UTC, dennis luehring wrote:
Am 30.03.2017 um 08:58 schrieb Ervin Bosenbacher:
That is the same, that came as a shock to me.
most compilers (for many languages) can optimize your super-trivial
example down to nothing - for at least the last 10 years or more
so whats the point? you're talkin about "performance is critical for me"
but missing even minor knowledge about todays compiler powers?
for a benchmark you need:
-loops, running millions of times, preventing IO and do now fall into
the completely-optimized-to-nothing-trap etc.
Tried again, threw in summing up a number 10 million times and repeat
the arrays 10 million times, I have used arrays on the stack for the D
version. And when I am talking about performance I am curious about CPU
bound stuff.
The D version:
import std.stdio;
void main()
{
long sum = 0;
foreach (long i; 0 .. 10000000) {
int[12] months = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30,
31 ];
int[3] first = months[0 .. 3];
int[3] second = months[3 .. 6];
int[3] third = months[6 .. 9];
int[3] fourth = months[9 .. 12];
Most of this code may be easily eliminated by dead-code removal. So you
probably just measure the summing loop alone. To be certain look at
disassembly.
---
Dmitry Olshansky
