Woo:
Writing a fast web server
Lisp Meetup #25 Eitaro Fukamachi

Thank you for coming.

I’m Eitaro Fukamachi
@nitro_idiot fukamachi

Looking for a Common Lisp job?
We’re hiring!
https://www.wantedly.com/projects/15144

(and 'web-application-engineer
'common-lisper)

(and 'web-application-engineer
'common-lisper)

(and 'web-application-engineer
'common-lisper)
server :(

Woo

Woo = Ultra Monster??
http://ultra.wikia.com/wiki/Woo_(kaiju)

Woo = Ultra Monster??

Woo = Ultra Monster??

• Web server for Clack applications
• HTTP/1.x
• Built on top of fast-http, QURI, libev
• Similar to Wookie, but even faster
Woo

Woo
https://github.com/fukamachi/woo#benchmarks

Woo
(woo:run
(lambda (env)
‘(200 (:content-type “text/plain”) (“Hello, World”))))
(clack:clackup
(lambda (env)
‘(200 (:content-type “text/plain”) (“Hello, World”)))
:server :woo)
Run with Clack

Let me tell
why I could make it so fast.

3 difficult things
in web servers

3 difficult things
• Network I/O is the largest bottleneck
• Need to handle a vast amount of requests
at once
• Need to handle various HTTP clients
(fast / slow / unstable)

Why fast?
1. Better architecture
2. The libev event library
3. Fast HTTP & URI parsing

Reason 1:
Better architecture

2 architectures:
Prefork vs Event-driven

Prefork
Worker
thread
Worker
thread
Worker
thread
master thread
Requests
accept connections
Responses
• Simple
• Fast for little
simultaneous
connections
• ex) Hunchentoot,
Unicorn, Apache

Prefork
Worker
thread
Worker
thread
Worker
thread
master thread
Requests
accept connections
Responses • Slow client can
cause performance
issue.
• like Mobile users
• Slowloris attack
blocking!
･･･
Problem

Event-driven
• Handle many
clients at the same
time
• Asnyc ACCEPT/
READ/WRITE
• ex) Woo, Wookie,
Tornado, nginxServer process
(single-threaded)
Event loop

Event-driven
• Single-threaded
Problem
Server process
(single-threaded)
Event loop

Woo took another way:
Multithreaded event-driven

Multithreaded event-driven
Server process
Event loop
listen on the same file descriptor
Server process
Event loop
Server process
Event loop

Reason 2:
The libev event library

libev
• Wrapper of epoll, kqueue, POSIX select, poll
• Thin
• Fast
• Poor Windows support
• I don’t think people run a web server on
Windows

First choice: cl-async
• Wookie built on top of cl-async
• cl-async was used to use libevent2
• Node.js uses libuv
• libevent2 might be the bottleneck
• cl-async has moved to libuv now

Reason 3:
Fast HTTP & URI parsing

HTTP parsing can be a bottleneck
• Wookie's largest bottleneck is HTTP parsing
• http-parse (uses regular expression)
• fast-http (byte to byte parser)
• 135 times faster than http-parse
• http://slideshare.net/fukamachi/writing-
a-fast-http-parser

URI parsing can be a bottleneck
• Wookie & Woo parses URI for dispatching
• PURI is *not really* fast
• QURI
• 6 times faster than PURI

Goal

Goal: What is fast enough?
• The initial goal was “Beating Node.js”
• Done
• Being the fastest web server in Common
Lisp
• Done

Got a great Pull Request

Future tasks

Future tasks
• Multithread performance
• SSL support
• HTTP/2 support

Multithread performance

Multithread performance
• Working in progress
• Legion

Status

Photo by Robert Couse-Baker licensed under the CC BY 2.0

Photo by Robert Couse-Baker licensed under the CC BY 2.0
Status
• Still alpha version
• Use at your own risk
• Tested with SBCL on Linux/Mac OS
• The latest bug:
• Cannot run in Americas (TZ problem)

Thanks.

EITARO FUKAMACHI
8arrow.org
@nitro_idiot fukamachi