Romain Beauxis <to...@rastageeks.org> writes:
> Le jeudi 15 juillet 2010 12:46:53, Goswin von Brederlow a écrit :
>> I don't see where that helps at all. I don't want to offload the IO into
>> threads and schedule them and Duppy seems to only handle IO tasks.
>
> I don't understand what you mean by IO tasks. Tasks in duppy are scheduled
> according to some events which, since it is select-based, are either an event
> on a socket or a timeout.
But I don't have a socket. The main thread runs and at some point it has
a Buffer.t that it needs to have checksummed. So that leaves timeout.
> Once scheduled, the action that the task does is anything you programmed.
> Once
> finished, the tasks can return an array of new tasks which are then put in
> the
> queue.
>
> In your case, you probably only need the timeout event, which would mean that
> as soon as you have a new tasks to perform, you submit it to the scheduler
> with timeout 0 and it will be processed by one of the threads as soon as
> possible..
So the code would be something like this?
let with_checksum buf sum _ =
reply_request ();
[]
let do_checksum buf _ =
let sum = ...
in
{ priority = 0; events = [`Delay 0.]; handler = with_checksum buf sum; }
let main_task events =
let rec loop tasks = function
[] -> tasks
| (`Read fd)::events ->
let buf = parse_request fd in
let task1 = { priority = 1; events = [`Delay 0.]; handler =
do_checksum buf; } in
let task2 = { priority = 0; events = [`Read fd]; handler = main_task; }
in
loop (task1::task2::tasks) events
in
loop events
let main () =
let scheduler = Duppy.create ()
in
for i = 1 to num_cores do
Thread.create (Duppy.queue ~priorities=(fun x -> x = 1) scheduler
"worker") ();
done;
Duppy.Task.add scheduler
{ priority = 0; events = [`Read server_socket]; handler = main_task; }
Duppy.queue ~priorities=(fun x -> x = 0) scheduler "main") ();
The main task will only process priority 0 events and bounce between
main_task and with_checksum while the worker threads process priority 1
events and do_checksum.
Correct?
>> Except if I pick Solution 1 and then it still doesn't help anything
>> since I can already run select in every thread. The IO should not be
>> scheduled by priorities and isn't the bottleneck anyway. Seems this
>> would just add overhead.
>
> The idea of duppy was to have only one select running among the multiple
> queue
> threads.
>
>
> Romain
MfG
Goswin
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