Quote
Amazing that it actually runs! I had imagined the biggest problem with the porting would have been the sockets. Perl on Windows possibly doesn't implement all socket features, like maybe nonblocking mode, or the can_read function of IO::Select. Look in the rpc_server_alt function that handles all client connections. There is a big while loop which iterates over all connected clients, reads any request data available up to that point, and then sends response data when sufficient request data (such as basic authentication) has been obtained. Trace the execution of this loop to see what runs normally and at what exact point the execution gets stuck.
So I've gone through the rpc_server_alt function and it doesn't appear to be hanging anywhere, the loop runs normally whether the worker is connected or not. But what I did find that seemed odd, was the it moves into code that appears to process the getwork request *as the worker disconnects*. Here's a short section of code I'm referring too. (Can't give line numbers as the unix2dos converter added a ton of whitespace, in theory it's after line 1400)
Code:
} else {
if ($vars->{longpoll}){
$vars->{rec}=2;
last;
}
$user->{getworks}++;
my $user_ip=$user->{host}; $user_ip=~s/:.*//;
my $limiter=$user_limiter{$user_ip};
my $lawful=user_lawful($limiter);
my $pair;
if ($lawful){ #only give good shares to lawful users <-indicative comment
$pair = $work_queue->dequeue_nb; <-confirmed code is executed only when worker is disconnecting
}
if (!$pair){
$pair=$solo_queue->dequeue;
}
$limiter->{got_works}++ if $limiter;;
my ($work, $pool_name) = @{$pair};
{
lock $work_dequeues;
$work_dequeues++;
}
logd("rpc getwork from $vars->{host} ($pool_name ".substr($work->{data}, 16, 8)." ".substr($work->{data}, 72, 8).") queue: ".$work_queue->pending."/".$WORK_QUEUE_SIZE."w ".$solo_queue->pending."so ".$submit_queue->pending."sh\n");
if ($vars->{longpoll}){
$vars->{rec}=2;
last;
}
$user->{getworks}++;
my $user_ip=$user->{host}; $user_ip=~s/:.*//;
my $limiter=$user_limiter{$user_ip};
my $lawful=user_lawful($limiter);
my $pair;
if ($lawful){ #only give good shares to lawful users <-indicative comment
$pair = $work_queue->dequeue_nb; <-confirmed code is executed only when worker is disconnecting
}
if (!$pair){
$pair=$solo_queue->dequeue;
}
$limiter->{got_works}++ if $limiter;;
my ($work, $pool_name) = @{$pair};
{
lock $work_dequeues;
$work_dequeues++;
}
logd("rpc getwork from $vars->{host} ($pool_name ".substr($work->{data}, 16, 8)." ".substr($work->{data}, 72, 8).") queue: ".$work_queue->pending."/".$WORK_QUEUE_SIZE."w ".$solo_queue->pending."so ".$submit_queue->pending."sh\n");
The rpc getwork message does appear, but only when the worker disconnects.
Again, I'm not strong with my Perl, so maybe this code is only supposed to run during disconnection, but the comment and the rest of the code implies it's removing a getwork from the internal queue and giving it to the worker. Would this be accurate?
. A big thank you from me. 
), all the work in the queue with the previous hash (including work from all other pools) is purged. About this time is also when longpoll is sent. The exact timing is a bit complicated, because while the pools typically, but not always, all work on the same block, the switching from one block to the next can happen up to 20 seconds apart between pools. So while you might have received a new share (and purged all old shares) from one pool, you might still receive shares with the old block hash from another pool for up to 20 seconds. Most of these shares will be rejected as stale once they are actually solved, so there is still some room for improvement in this area. Also, you don't want to send a longpoll signal ten times in 20 seconds, so you need a way to prevent double longpolls. For now, Multipool only sends longpoll when its own bitcoind reports a block hash change, but this could also be based on a cooldown timer.