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...@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 > >> > > -- https://mail.python.org/mailman/listinfo/python-list
