Fast UNIX Servers

Everyone ought start with Dan Kegel's classic site, "The C10K Problem" (still updated from time to time). Jeff Darcy's "High-Performance Server Architecture" is much of the same. Everything here is advanced followup material to these excellent works, and of course the books of W. Richard Stevens.

• "sendfile(): fairly sexy (nothing to do with ECN)" on lkml
• "mmap() sendfile()" on freebsd-hackers
• "sharing memory map between processes (same parent)" on comp.unix.programmer
• "some mmap observations compared to Linux 2.6/OpenBSD" on freebsd-hackers
• Stuart Cheshire's "Laws of Networkdynamics" and "It's the Latency, Stupid"

Queueing Theory

• "Introduction to Queueing"
• Leonard Kleinrock's peerless two-volume Queueing Systems

Event Cores

• epoll on Linux, /dev/poll on Solaris, kqueue on FreeBSD
• liboop, libev and libevent

Multithreading Event Cores

We must mix and match:

• Many event sources, of multiple types:
  • Socket descriptors, pipes
  • File descriptors referring to actual files (these usually have different blocking semantics)
  • Signals, perhaps being used for asynchronous I/O with descriptors (signalfd(2) on Linux unifies these with socket descriptors; kqueue supports EVFILT_SIGNAL events)
  • Timers (timerfd(2) on Linux unifies these with socket descriptors; kqueue supports EVFILT_TIMER events)
  • Condition variables becoming available
• One or more event notifiers (epoll or kqueue fd)
• One or more event vectors, into which notifiers dump events
  • kqueue supports vectorized registration of event changes, extending the issue
• Threads