Re^2: Coro, EV and cede

use strict;
use warnings;

use Coro;
use Coro::EV;

use Coro::LWP;
use LWP::Simple;

use Coro::Timer qw(sleep);


async {
    while (1) {
        CORE::select undef, undef, undef, 0.5;
        print "first\n";
        # my $r = get "http://www.perlmonks.org";
        # print length $r, "\n";
        # sleep 0;
        cede;
    }
};

async {
    while (1) {
        CORE::select undef, undef, undef, 0.5;
        print "second\n";
        # sleep 0;
        cede;
    }
};

EV::loop while 1;
[download]

output:

first
second
first
second
first
second
...
[download]

When uncomment

my $r = get "http://www.perlmonks.org";
print length $r, "\n";
[download]

got output:

first
second
second
second
second
second
second
second
[download]

Then uncomment "sleep 0" and got output :

first
second
76573
second
first
second
76570
second
first
second
76597
second
first
second
[download]

Comment on Re^2: Coro, EV and cede Select or Download Code

Replies are listed 'Best First'.
Re^3: Coro, EV and cede by Corion (Patriarch) on Apr 07, 2011 at 12:12 UTC
Depending on your version of LWP, LWP::Simple might or might not play nice with LWP::Coro. I know that at least for some versions prior to 5.827, LWP::Simple used its own socket factory instead of using what LWP::UserAgent did. You might want to inspect your module versions. Be careful when upgrading to LWP 6.x. If you use HTTPS connections, you will at least also need to install Mozilla::UA, because LWP 6 checks the validity of https certificates.	[reply]
Re^4: Coro, EV and cede by Nick Kostirya (Sexton) on Apr 07, 2011 at 12:36 UTC
No, I've checked at once - it doesn't depend on LWP. The same is going on with any EV-based module. For example, with AnyEvent::HTTP or with just EV.	[reply]
Re^3: Coro, EV and cede by zwon (Abbot) on Apr 07, 2011 at 13:00 UTC
The first result shows that `cede` works, as you get your switching. The problem starts after LWP comes in, and looking into Coro::LWP documentation, it looks like it does something rather cumbersome. I don't see it even tries to establish connection with the server. But if I replace CORE::select with just select everything is ok. I'd say you should try something else. I had positive experience with AnyEvent::HTTP, or maybe threads.	[reply] [d/l]
Re^4: Coro, EV and cede by Nick Kostirya (Sexton) on Apr 07, 2011 at 13:22 UTC
CORE::select is used to slow down the output. Its change to Coro select is equal to the call of Coro sleep 0. Remove the select at all if you wish. The problem will still persist with using AnyEvent::HTTP.	[reply]
Re^5: Coro, EV and cede by zwon (Abbot) on Apr 07, 2011 at 14:20 UTC
Yes, sorry, I wasn't clear, I meant "no Coro at all" when suggested AnyEvent::HTTP.	[reply]