Re: Potential performance improvements for Lua 5.2 beta

[Roberto Ierusalimschy <roberto@...>]

> First, on my Core i7 720 laptop, turning off #define MS_ASMTRICK
> saves a bit of time.

Does the code use the "regular" IEEE trick in that case
(LUA_IEEE754TRICK)? That used to cause problems with DirectX. Does
anyone know how is this problem currently?


> Okay, with those out of the way, I hit lvm.c.  For my particular
> benchmarks, the VM executes luaV_lessthan() and luaV_lessequal() a
> lot.  Adopting the Lua 5.1 type equality check helps out
> considerably.
> 
> [...]

Do you have any explanation to that? (Do the benchmarks execute
a lot of luaV_lessthan/luaV_lessequal for numbers or strings?)


> I then used an Instruction *pc and tried to update ci->u.l.savedpc
> at key intervals.  I did this quickly.  It might be wrong, but the
> performance improvement was huge.

How much is "huge"?

-- Roberto