Re: Timing Comparison?

I think I read that SBCL uses the GNUMP Bignum code. While, I have Martin stating several years ago that their LW does not.

That is what I suspect is the difference being seen here. And there is a shift around 2^69000 above which there is a noticeable slowdown in the LW code. Just saying… not criticizing. I think both are doing just great for my needs. 

Probably the breakpoint has to do more with memory management inside the Bignum libraries, since they might not be quite tuned into the underlying Lisp memory management system. But what do I know? I’m just speculating.



> On Nov 2, 2025, at 14:17, Yuri Davidovsky <[email protected]> wrote:
> 
> 
> 
>> On 2 Nov 2025, at 20:04, David McClain <[email protected]> wrote:
>> 
>> I’m willing to bet that the performance difference has very little to do with the quality of code generation from either SBCL or LWM compilers.
> 
> So what does it have to do with?
> 
>> The numbers involved in the Scheme timing test range from 2^6942 to 2^694242 in size. This is entirely in the domain of BIGNUM arithmetic, and I really doubt that either Lisp system encoded their BIGNUM arithmetic in themselves.
> 
> Do you mean, the values had to be constantly retrieved from the heap? If so, then you would be testing the memory subsystem performance and I doubt it would change drastically depending on whether you run your script in sbcl or lw. This is the reason why statically typed languages do not perform substantially better than php in web server context: the memory is the bottleneck as webservers constantly concatenate large strings from all over the place, do a lot of hash table lookups in some scenarios, traversing DB retrieval results and json objects processing, so on. 
> 
> When you move a lot of data around the computational performance becomes secondary as you won’t be saturating the cores.


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