Hi I prepared a PR with additional tests for the Free packag kotlinlang #arrow-contributors

Hi, I prepared a PR with additional tests for the Free package; and, I added a new benchmarking project for the trampoline part... Interesting: for calculations of the Fibonacci sequence, there is approximately 30% difference between the Trampoline/Eval approaches.

👏 1

Note : I will push this PR as soon as one of my proxies will be available 😡

pakoito

01/30/2020, 1:41 PM

30% improvement? wow!

PhBastiani

01/30/2020, 1:46 PM

30% in favour of Eval... I only added some additional tests.

Jannis

01/30/2020, 1:50 PM

Does your benchmark rerun the computation with the same

Eval

multiple times? Because

Eval

memoizes results in some cases

I actually use that quite heavily in my prettyprinter because the same lazy structure gets traversed over and over again

PhBastiani

01/30/2020, 1:59 PM

yep, you're right... I think that jmh reuses the same resource

Jannis

01/30/2020, 2:03 PM

You can set an isolation level per invocation afaik

PhBastiani

01/30/2020, 2:14 PM

I used Scope.Thread as isolation... I think that I can play with the Setup annotation... I will check again

raulraja

01/31/2020, 7:19 PM

We need to investigate what we can do at a compiler plugin level to support trampolining automatically without building up data structures

Jannis

01/31/2020, 8:07 PM

This leads into control flow analysis and predicting stack depth, which is really hard. Unless you trampoline everything, which may or may not hurt performance, but that's worth testing.

I think looking at the leanest structure possible is important. And between

AndThen

Eval

Trampoline

and

IO

I think that may be

AndThen

because it fuses function calls.

AndThen

however will still cause overflows if it is invoked at depth.

Eval

and

Trampoline

both trampoline everything and thus don't need this.

IO

is usually invoked at the edge and hence can fuse function calls freely because of that.

@PhBastiani can you try

AndThen

in your tests as well? Would be interested in the outcome ^^

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