ANN: Dogelog Runtime, Prolog to the Moon (2021)

[Mostowski Collapse]

Concerning garbage collection, did a long term
measurement for the first time. I measured
LIPS for fibonacci numbers, i.e. time(fibo(23,X)).

Doing the same thing 16 times, how long does it take?
Here is a depiction how the LIPS relatively differ in each run:
https://gist.github.com/jburse/c85297e97091caf22d306dd8c8be12fe#gistcomment-3896343

I can also calculate the mean and standard deviation. 
>From this we see that Python has a 5% deviation, whereas
GraalVM has a 1% deviation. So the GraalVM garbage

collector works more evenly? Disclaimer, I measured
different time spans, the GraalVM is now 7x times
faster than Standard Python, so this is inconclusive.

Mostowski Collapse schrieb am Freitag, 17. September 2021 um 10:58:57 UTC+2:
> The Prolog garbage collection that does 
> the movement on the variable trail is only 
> a very small fraction of the runtime. 
> 
> The garbage collection time is measured. 
> Some measurements with version 0.9.5 
> took the following values: 
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
> % Standard Python Version, Warm Run 
> % ?- time(fibo(23,X)). 
> % % Wall 3865 ms, gc 94 ms, 71991 lips 
> % X = 46368. 
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
> % GraalVM Python Version, Warm Warm Run 
> % ?- time(fibo(23,X)). 
> % % Wall 695 ms, gc 14 ms, 400356 lips 
> % X = 46368. 
> 
> The "gc" timing measures Prolog garbage 
> collection. So you get the following percentage 
> of time spent in Prolog garbage collection: 
> 
> Standard Python: 94 / 3865 = 2.4% 
> 
> GraalVM Python: 14 / 695 = 2.0% 
> 
> I consider this a good result. The Prolog 
> garbage collection is not utterly expensive. 
> The detecting the movement and performing 
> 
> the variable movement on the trail, doesn't 
> take so much time. Currently the garbage collection 
> in Dogelog runtime is configured towards 
> 
> synchronization with 60FPS, it does around 
> 60-120 garbage collections per second. This 
> is less than what SWI-Prolog does. 
> 
> SWI-Prolog has a much higher GC rate. 
> 
> But I did not yet measure new version 0.9.6. 
> 
> Mostowski Collapse schrieb:
> > No its cooperative. Usually objects do get 
> > garbage collected by the native garbage collector 
> > of the host language in Dogelog runtime. 
> > 
> > The Prolog garbage collection is only to help 
> > the host language garbage collector when you have 
> > a deep recursion in Prolog. 
> > 
> > You can then reclaim intermediate variables. 
> > A simple example to test the slightly idio- 
> > syncratic Prolog garbage collection is: 
> > 
> > fibo(0, 1) :- !. 
> > fibo(1, 1) :- !. 
> > fibo(N, X) :- 
> > M is N-1, fibo(M, Y), 
> > L is M-1, fibo(L, Z), 
> > X is Y+Z. 
> > 
> > When running fibo(30,X) SWI-Prolog does around 
> > 800 garbage collections to keep the environment 
> > small. But SWI-Prolog allocates all its objects 
> > 
> > only very seldom on the heap. It uses its own 
> > stack. On the other hand Dogelog runtime creates 
> > everything on the heap. And completely relies on 
> > 
> > the host language garbage collection. It only 
> > helps the host language garbage collection it 
> > that it performs from time to time this movement: 
> > 
> > Before: 
> > 
> > -->[ A ]-->[ B ]-->[ C ]--> 
> > 
> > After: 
> > 
> > -->[ A ]---------->[ C ]--> 
> > 
> > A,B,C are objects of type Variable. The above 
> > movement only happens for objects of type Variables 
> > from time to time. For objects of type Compound 
> > 
> > no modifications are done during Prolog garbage 
> > collection. The Prolog garbage collection aggressively 
> > nulls the Variable object B, and the host language 
> > 
> > later will garbage collect what the Variable object B 
> > was pointing to. But the Variable object B might 
> > nevertheless have point to something shared with 
> > 
> > some other Variable object or a local or a global 
> > Python variable, or a Compound. This is then all 
> > courtesy of the host language to decide reachability. 
> > 
> > Chris Angelico schrieb: 
> >> On Fri, Sep 17, 2021 at 7:17 AM Mostowski Collapse 
> >> <janb... at fastmail.fm> wrote: 
> >>> 
> >>> About Exceptions: Thats just building ISO core 
> >>> standard Prolog error terms. 
> >>> 
> >>> About Garbage Collection: Thats just Prolog 
> >>> garbage collection, which does shrink some 
> >>> single linked lists, which ordinary 
> >>> programmig language GC cannot do, 
> >>> 
> >> 
> >> Okay, so.... you're building your own garbage collection on top of 
> >> Python's, and you're wondering why it's slow? 
> >> 
> >> Change your code to not try to implement one language inside another, 
> >> and you'll see a massive performance improvement. 
> >> 
> >> ChrisA 
> >> 
> >