On Wednesday, 30 March 2016 at 22:49:24 UTC, ag0aep6g wrote:
When byCodeUnit takes no time at all, isn't 1µs infinite times
slower, instead of 100 times? And I think byCodeUnits's 1µs is
so low that noise is going to mess with any ratios you make.
It's not that it's taking no time at all, it's just that it's
less than 1 hecto-nanosecond, which is the smallest unit that
benchmark works with.
Observe what happens when the times are no longer averaged, I
also made some other changes to the script:
import std.datetime;
import std.stdio;
import std.array;
import std.utf;
import std.uni;
enum testCount = 1_000_000;
void test(char[] var)
{
auto a = var.array;
}
void test2(char[] var)
{
auto a = var.byCodeUnit.array;
}
void test3(char[] var)
{
auto a = var.byGrapheme.array;
}
void main()
{
import std.conv : to;
import std.random : uniform;
import std.string : assumeUTF;
// random string
ubyte[] data;
foreach (_; 0 .. 200)
{
data ~= cast(ubyte) uniform(33, 126);
}
auto result = to!Duration(benchmark!(() =>
test(data.assumeUTF))(testCount)[0]);
auto result2 = to!Duration(benchmark!(() =>
test2(data.assumeUTF))(testCount)[0]);
auto result3 = to!Duration(benchmark!(() =>
test3(data.assumeUTF))(testCount)[0]);
writeln("auto-decoding", "\t\t", result);
writeln("byCodeUnit", "\t\t", result2);
writeln("byGrapheme", "\t\t", result3);
}
$ ldc2 -O3 -release -boundscheck=off test.d
$ ./test
auto-decoding 1 sec, 757 ms, and 946 μs
byCodeUnit 87 ms, 731 μs, and 8 hnsecs
byGrapheme 14 secs, 769 ms, 796 μs, and 6 hnsecs
