Re: Lua is faster than Java?

[David Given <dg@...>]

On Monday 25 July 2005 23:07, Mike Pall wrote:
[...]
> I think it was Rici who suggested to me on IRC that a
> sufficiently optimized and inlined hash method dispatch
> comes pretty close to the performance of multi-level linear
> dispatch. The above data supports that reasoning.

*nods*

Hash tables are disturbingly fast --- a well tuned hash table can be faster 
than an AVL tree, for example. (But the 'well tuned' bit is *really 
important*.)

One technique we use extensively at work is to have some complex data 
structure --- AVL tree, hash table, etc --- with a very small cache; 
typically only four slots or so. Doing a cache lookup can then be done 
inline; on the ARM you should be able to do it with a certain amount of 
cheating in four instructions. Depending on your access patterns this can 
have a surprisingly good effect.

-- 
"Curses! Foiled by the chilled dairy treats of righteousness!" --- Earthworm 
Jim (evil)

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