Re: LW compiler optimizations

Heh! Tim!! No need to get so hot. 

I admit I didn’t read about your macro at all. 

And I really do appreciate your contrary perspective, so please don’t leave.

But the fact remains that I cannot attain your 1.1 ns timing. The closest I come is 6.7 ns/MAC pair.



> On Jan 14, 2025, at 15:57, Tim Bradshaw <[email protected]> wrote:
> 
> On 14 Jan 2025, at 22:21, David McClain <[email protected]> wrote:
>> 
>> But this indicates that using a displaced array costs me nearly 5x performance degradation, as opposed to your claim of 1% penalty.
> 
> I am sorry I am now going to lose my temper.
> 
> LEARN TO FUCKING READ.
> 
> I will repeat what I actually wrote which you have repeatedly misquoted: 
> 
> So let's summarize: the demonstrated performance cost of displaced arrays in an existing CL implementation, after a little macro, is *under one percent*.
> 
> No, I know this is hard, but you need to read all of that sentence.  All of it.  In case that really is too hard, here are two important bits:
> 
> "after a little macro": this is the macro which is described in that message, and which is included in some of the code I posted.  It turns a displaced array into its underlying simple array and optionally provides a macro to reference that underlying array with a suitable offset.
> "in an existing CL implementation".  Being, in this case, as I made clear, SBCL (although LW can be persuaded, as is demonstrated by the tsda/tsoa function in ts-dar.lisp.
> 
> I know it's hard to read what people say, but really, it is not that hard.
> 
> OK, I feel at this point the LW people will be fully justified from removing me from the list.  That's fine.
> 
> --tim
> 
> 
>