Re: LuaJIT performance

[Alexander Gladysh <agladysh@...>]

On Mon, Aug 10, 2009 at 04:36, Mike Pall<mikelu-0908@mike.de> wrote:
> Alexander Gladysh wrote:
>> I, personally, am interested in LJ2 for iPhone (which is ARM-based).
>> As I intend to reuse existing (x86) game logic code on it, I would
>> need floating point support.

> Ok, but you may be in for a nasty surprise: the 3GS has an ARM
> Cortex-A8 CPU which only has VFPlite. This is actually a step back
> from the previous models which had an ARM 1176JZ(F)-S with a full
> VFP unit. And since the vector mode of VFP is officially deprecated,
> you're in for more surprises in the future.

Ugh, that is not nice.

> Not to squash your hopes, but I suggest you try to measure whether
> the iPhone FP performance can keep up with your requirements.
> Maybe try some simple double-precision FP benchmarks in C (don't
> compile as Thumb code or you get softfp).

Well, while I do need floating point support for my Lua code to work
properly, it is not that computationally expensive. Actually, plain
Lua interpreter seems to be fast enough for my current needs. But I'd
like to be able to stuff even more logic in it in future -- so some
JIT-ting should be quite handy.

<...>

> Thank you to both of you for the quick feedback!

You're welcome!

Alexander.