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- Subject: Re: How fast is LuaJIT supposed to be?
- From: Axel Kittenberger <axkibe@...>
- Date: Fri, 21 Jan 2011 20:34:24 +0100
On Fri, Jan 21, 2011 at 8:10 PM, Alexander Gladysh <email@example.com> wrote:
> On Fri, Jan 21, 2011 at 22:08, Steve Litt <firstname.lastname@example.org> 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)