A lot of people have been complaining about APC's stability issues. In fact, they get angrier when I mention that it works for Yahoo!. During the FIFA slams on the servers, we put in a few extra things in APC to make it withstand the hammering. Now, a couple of these protections were borrowed from code that Y! already had lying around and a few more of them were BSD specific. But the short story is that I can never push those changes to the open source version. Nor can I even rewrite the same features after reading Y! © code which does the same, at least not while I'm here.
*But*, one feature that we borrowed was discussed quite a while back on the php-internals mailing list. If someone among you think that they know enough to understand what this means and implement it under the php license, maybe it might be accepted as a patch to php.
All it needs is some elbow grease and a bit of unix magic :)--
signal(i, SIG_DFL); /* crunch, crunch, crunch */
-- Larry Wall in doarg.c from the perl source code