Am 03.08.2011, 19:21 Uhr, schrieb Steven Schveighoffer
<schvei...@yahoo.com>:
On Wed, 03 Aug 2011 13:14:50 -0400, Andrej Mitrovic
<andrej.mitrov...@gmail.com> wrote:
Take a look at this:
import std.stdio;
import core.thread;
void main()
{
foreach (x; 0 .. 1000)
{
Thread.sleep(dur!("usecs")(999));
writeln(x);
}
foreach (x; 0 .. 1000)
{
Thread.sleep(dur!("usecs")(1000));
writeln(x);
}
}
Compile and run it. The first foreach loop ends in an instant, while
the second one takes much much longer to finish, which is puzzling
since I've only increased the sleep while for a single microsecond.
What's going on?
I can only imagine that the cause is the implementation is using an OS
function that only supports millisecond sleep resolution. So
essentially it's like sleeping for 0 or 1 millisecond. However, without
knowing your OS, it's hard to say what's going on. On my linux install,
the timing seems equivalent.
-Steve
I would have guessed it comes down to time shares. If the scheduler works
at a rate of 1000Hz, you get 1ms delays, if it works at 250Hz you get 4ms.
Going down to an arbitrarily small sleep interval may be unfeasible. It's
just an idea, I haven't actually looked that up.
