mojo using 100% CPU

[Jeremy]

All,

I was doing some stress testing for an embedded app that sends lots of websocket messages, and I can't understand some odd behaviour. Basically mojo stalls using 100% CPU for many seconds. Doing the following (to simulate heavy load):

         for (1..10000) {

           $sc->{websocket}->send({text => $payload});

         }

Will send 10000 messages to the client (they all arrive) but then mojo stalls using 100% CPU for 19 seconds or so. Running nytprof, I get this:

10000

1

1

19.2s

19.2s

Mojo::EventEmitter::unsubscribe

50	10000	3.89ms			if ($cb) {
51	10000	19.1s			$self->{events}{$name} = [grep { $cb ne $_ } @{$self->{events}{$name}}];
52	10000	9.66ms			delete $self->{events}{$name} unless @{$self->{events}{$name}};

Looking at the above code it seems to suggest that a callback is being used, but I am not sure where/how it was created? I do use the following paradigm in my code, could this be the cause of the problem?

my $id = Mojo::IOLoop->client({address => '127.0.0.1', port => 5001} => sub {

  my ($loop, $err, $stream) = @_;

  ...

  $stream->on(read => sub {

    my ($stream, $bytes) = @_;

    # Process input 

    ...

    [call a function that would send these 10000 messages to the websocket]

  });

});

Thanks,

[sri]

         for (1..10000) {

           $sc->{websocket}->send({text => $payload});

         }

This is fundamentally flawed code. All your're doing here is building 10000 websocket

frames and appending them one by one to a write buffer. No actual I/O is performed here and

lots of time wasted that could be spent doingother stuff concurrently.

--

sebastian

[jez_...@hotmail.com]

Hi,

Thanks for the reply. The above code is to highlight the 'problem', but I certainly accept that I could be doing something wrong and this isn't a problem at all:)

Flipping the question around slightly, if I know I've got 10000 messages sitting in an event queue that needs to be sent to a websocket, how should I do it with out causing this CPU spike? Should I call one_tick or something similar?

To give a little more information, I'm using an incoming socket to notify me that there is (at least one) event to be handled in a thread safe event queue, then in my event handler I have something like this (pseudo code):

sub EventHandler {
  while ($eventQueue->HasMessages) {
    my ($messageCode,$messageObject) = $eventQueue->GetMessage();
      if ($messageCode == 12) {
         #in reality we would have multiple websockets here
         $websocket->send({text => $messageObject});
      }
  }
}

Regards,