Solaris 10 oops. oops. oops. oops.
So, I used dtrace to diagnose a pretty subtle performance problem with Ecelerity a while ago and just got around to implementing an enhancement to obviate that bottleneck. This would be asynchronous socket shutdowns and closes under situations that were "challenging" before.
I built out a generalized asynchronous socket shutdown and close framework and deployed it throughout the application. On Solaris, our event system now handles the socket() calls, the port_associates() and port_diassociates(), read/write/readv/writev/send/recv/etc. However, now in all possible places we asynchronous the shutdown() and close() to other threads to avoid some minor performance issues. Basically, the same thing the lingerd patch to Apache does.
However... I launched the new code in our test environment and BOOM!
# mdb unix.2 vmcore.2 Loading modules: [ unix krtld genunix specfs ufs ip sctp usba fctl nca lofs nfs random ipc crypto sppp ] > ::stack vpanic(fe96c300) turnstile_block+0x2ff(d07ea5f0, 0, d5a07700, fec022f8, 0, 0) mutex_vector_enter+0x2d4(d5a07700) getf+0x3f(3dc) port_dissociate_fd+0x42(d3842180, 3dc) portfs+0x131() sys_sysenter+0xdc()and
# mdb unix.5 vmcore.5 Loading modules: [ unix krtld genunix specfs ufs ip sctp usba fctl nca lofs nfs random ipc crypto sppp ] > ::stack vpanic(fe96c300) turnstile_block+0x2ff(d07be000, 0, d2188348, fec022f8, 0, 0) mutex_vector_enter+0x2d4() port_close_pfd+0x2f(d43742c0) port_close_fd+0x58(d43742c0, 45) closeandsetf+0x2db(45, 0) close+0xd() sys_sysenter+0xdc()
6 panics in 60 minutes. Yikes?! Time to call Sun on the tele.