Re: How fast is LuaJIT supposed to be?

[Steve Litt <slitt@...>]

On Friday 21 January 2011 14:34:24 Axel Kittenberger wrote:
> On Fri, Jan 21, 2011 at 8:10 PM, Alexander Gladysh <agladysh@gmail.com> 
wrote:
> > On Fri, Jan 21, 2011 at 22:08, Steve Litt <slitt@troubleshooters.com> 
wrote:
> >> On Friday 21 January 2011 03:48:02 Axel Kittenberger wrote:
> >>> Ah, a sieve of eratosthenes (there are various ways to get primes). I
> >>> suppose you will find a considerable perfomance increase (native and
> >>> jit) if you use "candidate" as a local variable you pass as argument
> >>> and return value to find_next_candidate() instead of storing it as
> >>> "candidate" key in the prime array.
> >>
> >> Is table lookup really more expensive than passing in as an arg and
> >> passing back as a return? Ugh!
> >
> > Try LJ2, you will think about these implementation details no longer. :-)
> 
> Strange I didnt see that email :-/
> 
> Lua Tables are hashtables. Putting and getting stuff from a hashtable
> is of course slower than from a local variable (that is either on
> stack or even a register)

How much slower? To my way of thinking, tables of key/value pairs are the 
heart and soul of Lua. I'd hate to start worrying about speed when using them.

SteveT

Steve Litt
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