I believe the accept is failing under heavy load.
I was puzzled by the weird shell parsing and wondered if that was part of the problem so I whipped up a lame threaded client that can reliably "crash" the server on my Debian system.
#!/usr/bin/perl
use 5.10.0;
use strict;
use warnings;
use Socket;
use threads;
my $rendezvous = shift || 'catsock';
my $max_clients = 10;
$_->join for map { threads->create( \&run_client ) } 1 .. $max_clients
+;
sub run_client {
my $sock;
unless ( socket($sock, PF_UNIX, SOCK_STREAM, 0) ) {
warn "socket: $!";
return;
}
unless ( connect($sock, sockaddr_un($rendezvous)) ) {
warn "connect: $!";
return;
};
while ( defined(my $line = <$sock>) ) {
print $line;
}
}
The next thing I noticed was that an strace of the server seemed to exit normally. Immediately after the for loop I added
print "\n\nWTF?\n\n";
and got
$ perl -T 855342.pl
855342.pl 22345: server started on catsock at Tue Aug 17 11:00:49 2010
855342.pl 22345: connection on catsock at Tue Aug 17 11:00:51 2010
855342.pl 22345: begat 22348 at Tue Aug 17 11:00:51 2010
855342.pl 22345: connection on catsock at Tue Aug 17 11:00:51 2010
855342.pl 22345: begat 22350 at Tue Aug 17 11:00:51 2010
855342.pl 22345: connection on catsock at Tue Aug 17 11:00:51 2010
855342.pl 22345: begat 22352 at Tue Aug 17 11:00:51 2010
855342.pl 22345: connection on catsock at Tue Aug 17 11:00:51 2010
855342.pl 22345: begat 22355 at Tue Aug 17 11:00:51 2010
855342.pl 22345: connection on catsock at Tue Aug 17 11:00:51 2010
855342.pl 22345: begat 22356 at Tue Aug 17 11:00:51 2010
WTF?
That means that the for condition accept(Client,Server) || $waitedpid; is evaluating to false. Just before the exit, the strace shows
accept(3, 0x7fff3015acc0, [4096]) = ? ERESTARTSYS (To be restart
+ed)
Therefore, I believe the accept is failing under heavy load and
my advice is to always check the return value from accept.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.