Photon v0.13.0 with offload

[Dmitry Olshansky]

On Saturday, 16 August 2025 at 14:51:45 UTC, Dmitry Olshansky 
wrote:
> On Saturday, 16 August 2025 at 09:43:02 UTC, GL wrote:
>> On Wednesday, 13 August 2025 at 13:28:26 UTC, Dmitry Olshansky 
>> wrote:
>>
>>> I need to think a little more about it but I would likely 
>>> ship it in the next release. Soonish :)
>>
>> Thank you!
>> I will wait with great impatience...
>
> With new version v0.12.2 basic ZeroMQd example runs fine. Of 
> other things HTTP server finally scales very well up to 48 
> cores and is faster than anything I've tried. (see photon-http 
> 0.5.4)

Actually that should be 0.5.5 :)

And v0.13.0 brings new feature - offload to run compute intensive 
tasks outside of scheduler. Certain syscalls are automatically 
routed through it to avoid blocking fibers such as file I/O. Here 
is simple example using goOnSameThread to make sure we are 
actually sharing just a single eventloop thread out of many and 
yet it doesn't block.

import photon;

double gauss(double a, double b, double function(double) f, 
double step) {
     double sum = 0.0;
     for (double x = a; x < b; x += step) {
         sum += (f(x+step) + f(x))/2 * step;
     }
     return sum;
}

void boom() {
     throw new Exception("Boom!");
}

long fib(long n) {
     if (n <= 2) return 1;
     else {
         return offload(() => fib(n-1)) + offload(() => fib(n-2));
     }
}

void main() {
     startloop();
     go({
         goOnSameThread({
             writeln("Blocking computation");
             writeln("Integral:", gauss(0.0, 10.0, x => x*x, 
1e-7));
         });
         goOnSameThread({
             writeln("Blocking computation");
             writeln("Integral:", gauss(0.0, 10.0, x => x*x, 
1e-7));
         });
         goOnSameThread({
             writeln("Nonblocking computation");
             writeln("Integral: ", offload(() => gauss(0.0, 10.0, 
x => x*x, 1e-7)));
         });
         goOnSameThread({
             writeln("Nonblocking computation");
             writeln("Integral: ", offload(() => gauss(0.0, 10.0, 
x => x*x, 1e-7)));
         });
         goOnSameThread({
             writeln("Catching exception from offloaded 
computation");
             try {
                 offload(&boom);
                 assert(0);
             } catch(Exception e) {
                 assert(e.msg == "Boom!");
             }
         });
         goOnSameThread({
             writeln("Recursive offload");
             writeln("Fib(15):", offload(() => fib(15)));
         });
     });
     runFibers();
}

Other photon examples:
https://github.com/DmitryOlshansky/photon/tree/master