Re: [Qemu-devel] [RFC][PATCH] tcg: allocate memory to spill registers on startup

[Paul Brook]

On Friday 10 April 2009, Aurelien Jarno wrote:
> On Fri, Apr 10, 2009 at 03:44:55PM +0100, Paul Brook wrote:
> > On Friday 10 April 2009, Aurelien Jarno wrote:
> > > +    assert(size != TCG_MAX_TEMPS * sizeof(tcg_target_long));
> >
> > Shouldn't this be >= ?
>
> When I wrote that, I thought that the two sizes have to match, 

In that case I think the assert is completely wrong. You're asserting that the 
two values are not equal. IIRC there's bits in the TCG headers that disable 
asserts by default - I've been bitten by this before.

> but you are right, the frame size can actually be bigger.
> Any other comment?

What were you benchmarking? Translation speed or execution speed?
I'd guess that your new code speeds up the translator, but makes the resulting 
code less cache friendly.

Maybe if I see your subsequent optimization it might make more sense, though 
I'm suspicious of tcg-target doing register allocation/spilling itself.

Paul