- lev is a platform for building servers more easily than Node. It is based on Lua and libuv and is faster and uses less memory than Node. - The founders of lev overhauled lua-event and reimplemented many parts like cBuffer and MessagePack for better performance. - lev supports multicore processing out of the box and has a redesigned API compared to lua-event.

1. lev
Tokyo Node Gakuen 7
periods
2012/09/18
@kazupon
(kazu_pon)
1

2. Introduction
@kazupon
name: kazuya kawaguchi
twitter: kazu_pon
Job
OKI -> Bluebridge -> Freelance (now)
Flont-end Engneer? Back-end Engneer?
Work
Zenback, and others ...
Node
connect-kyoto
kyotocabinet-node
SabaDB
2

3. What is `lev` ?
Lua for Event-based IO
libuv + LuaJIT
EventLoop Lua, JIT Engine
`lev` is platform/language that start
up a server more easily than Node
3

4. Concepts of `lev`
Fast !!
`lev` can easily reach over 10,000 requests per
core , machine and scales near-linearly.
Low Memory !!
At start-up, `lev` only allocates around 2MB
and after benchmarking HTTP a little over 3MB.
Easy C-libraries integration !!
`lev` is based on lua which has a very simple
and compact C ABI.
4

5. Who founded `lev` ?
founder: @kristate
cofounder: @hkanamur
`lev` is everything great about Node,without
the "BS" of JS.
― kristopher tate, lev founder
@kristate @hnakamur
5

6. Video message
from @kristate
http://www.ustream.tv/recorded/25501929
21:25-25:10
6

7. `lev`
Fork from luvit, overhaul,
reimplementation
$ git diff --shortstat 173c91...master
https://github.com/connectFree/lev/compare/
173c91e383361fb09c1e7f973f6e24bec0d4fcec...master
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8. `lev`
connectFree open source
Apache 2.0 license
8

9. Contributors
@hnakamur @dvv
@kristate
@xming @kazupon
9

10. Community
github
http://github.com/connectFree/lev
IRC
freenode: #levdev, #lev-jp
10

11. Demo
chat
bit.ly/levchat
11

12. Benchmark
Measurement item
Requests per second
Memory usage
Measurement Pattern
ab -n 2000 -c 1
ab -n 2000 -c 10
ab -n 2000 -c 100
12

13. Benchmark
Enviroments
100BASE-T
Ethernet
Client direct connect Server
MacBook Pro Retina, Mid 2012 Macbook, Early 2009
* CPU: 2.6 GHz Intel Core i7 * CPU: 2GHz Intel Core 2 Duo
* RAM: 16GB 1600 MHz DDR3 * RAM: 4GB 667 MHz DDR2 SDRAM
* Disk: 512GB * Disk: 256GB
APPLE SSD SM512E FUJITSU MHZ2250BH FFS G1 Media
* OS: Mac OS X 10.8 Mountain SATA
Lion * OS: Mac OS X 10.7.3 Lion
13

14. Benchmark
Version
Node: 0.8.9
luvit: 0.5.0
lev: b03a16d (git commit hash)
14

15. Benchmark
Results - Requests per second
ab -n 2000 -c 1
ab -n 2000 -c 10
ab -n 2000 -c 100
0 3750 7500 11250 15000
Node luvit lev
15

16. Benchmark
Results - Memory usage (output of ps)
startup
after ab -n 2000 -c 1
after ab -n 2000 -c 10
after ab -n 2000 -c 100
0 5 10 15 20
Node luvit lev
16

17. Implementation
We overhauled luvit, and
reimplementation
cBuffer
MessagePack
Build-in multicore
Redesigned API
Modules
Build system
Platform
17

18. cBuffer
Buffer module
lev_slab_allocator_t mem_1k; lev_slab_allocator_t mem_8k;
MemBlock pool[]; MemBlock pool[];
C bytes: 1024 bytes: 1024
... x8
implementation lev_slab_allocator_t mem_16k;
Allocated MemBlock pool[];
bytes: 1024
special slab ... x16
allocator lev_slab_allocator_t mem_64k; lev_slab_allocator_t mem_1024k;
MemBlock pool[]; MemBlock pool[];
Byte array bytes: 1024
... x64
bytes: 1024
... x1024
Seamless MemSlice
conversion to char *slice;
size_t until;
string lev.Buffer
18

19. MessagePack
lua-msgpack-native (*1)
author: @kengonakajima
full scratch
C implementation
5x ~ 10x faster than mplua (*2)
20x ~ 50x faster than luvit's JSON
Customization for cBuffer
build-in module
*1 https://github.com/kengonakajima/lua-msgpack-native
*2 https://github.com/nobu-k/mplua
19

20. Build-in multicore
Default build-in
Specify number of core at start up
$ lev -c 8 ./examples/http-simple-server.lua
Master-Worker process model
Shared listening socket
Communication: IPC
Messge format: Messagepack
Event notification: callbox
20

21. Redesigned API
Ex: fs
sync
local fs = require('lev').fs
local err, fd = fs.open('LICENSE.txt', 'r', '0666')
...
async
local fs = require('lev').fs
fs.open('LICENSE.txt', 'r', '0666', function(err, fd)
...
end)
21

22. Modules
lev timer
fs pipe
callbox
mpack
json
dns
tcp
udp
http
22

23. Build system
Makefile build system base
Future: cmake build system (by @xming)
Not use GYP build system
23

24. Platform
*NIX
Linux, Darwin, Freebsd, and other ...
Not support Windows
24

25. Loadmap (Wishlist)
Build-in Web application framework
Build-in Package managment tool
Choice regular expression library
Resolve callback hell
... etc
25

26. Conclusion
`lev` is platform/language that start up
a server more easily than Node
Fast
Low memory
Easy C-libraries integration
Overhauled and redesigned cBuffer base
Support multicore with build-in
26

27. Special Thanks !!
@kristate, @hnakamur
lev community
luvit team and luvit commuity
Mike Pall (LuaJIT)
@kengonakajima (lua-msgpack-native)
libuv, Node conributers, and Joyent
27

28. Thank you
for listening to my
session
28

29. Question ?
29

30. Reference
luvit
http://luvit.io/
https://github.com/creationix/
nodeconf2012
http://coderwall.com/p/gkokaw
benchmark data
git://gist.github.com/3727820.git
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