On Thursday, 21 September 2017 at 18:55:04 UTC, Vadim Lopatin
wrote:
On Thursday, 21 September 2017 at 18:49:00 UTC, bitwise wrote:
On Thursday, 21 September 2017 at 08:01:23 UTC, Vadim Lopatin
wrote:
[...]
Doesn't vibe-d use Fibers?
I tried to build a simple web server with a fiber-based
approach once - it was horribly slow.
I hope C# (and soon C++) style stackless resumable functions
will eventually come to D.
It does. But Golang uses them, too. Goroutines.
Indeed. I'm reading about them right now, and they seem to be
"multiplexed". I wonder if Vibe.d does something similar.
The fact that you've observed lower CPU usage by the D version
makes me think some kind of scheduling or thread-priority issue
is the cause.
For example, on windows, the default timer frequency is very low.
It would seem reasonable to get 1000 iterations per second in the
example below, but you get ~64.
`
auto now = steady_clock::now();
auto done = now + milliseconds(10000);
int iterations = 0;
while(steady_clock::now() < done) {
++iterations;
Sleep(1);
}
cout << (iterations / 10) << endl;
`
When I wrap the above code with timeBeginPeriod(1) and
timeEndPeriod(1), I get ~550 on my machine.
IIRC, you get similar behavior on MacOS(maybe linux too?) unless
you explicitly raise the thread priority.
https://msdn.microsoft.com/en-us/library/windows/desktop/dd757624(v=vs.85).aspx
So if you're benchmarking anything that sleeps regularly, like an
event based framework, something like
timeBeginPeriod/timeEndPeriod may help.
