FWD: Test reader speed of Guile 3.0.6 in Lilypond

[Dr. Arne Babenhauserheide]

Hi,

due to the reader-rewrite, I asked in the lilypond-list for testing,
because they are likely the strongest power-user of the reader.

Han-Wen Nienhuys checked performance in the benchmark suite:

> $ cat ../bench.ly
> #(define (microseconds)
>   (let* ((t (gettimeofday))
> (us (/ (cdr t) 1000000.0)))
>    (+ (car t) us)))
>
> #(define start (microseconds))
>
> % \include "bench-largeexp.ly"
> \include "bench-manysmall.ly"
>
> #(newline)
> #(display (- (microseconds) start))
>
> Parsing & evaluating '(1 2 3) 200 times.
> - guile 1.8: 1.25ms
> - guile 2.2: 3.2ms
> - guile 3.0.6: 2.08ms
>
> Parsing & evaluating the giant expression in define-grobs.scm once:
>
> - guile 1.8: 10.6ms
> - guile 2.2: 166ms
> - guile 3.0.6: 71ms
>
> Parsing & evaluating the giant expression in define-grobs.scm once
> (but quoted, ie. not real evaluation):
>
> - guile 1.8: 10.0ms
> - guile 2.2: 13ms
> - guile 3.0.6: 12.8ms
>
> In summary, the read speed itself for large expressions is on the same
> order as 1.8, but for many small expressions (which is a much more
> common use-case) there is still a 60% slowdown.

>> asking here because I want to avoid surprising and avoidable changes
>> that block Lilypond. I consider Lilypond to be the most important
>> flagship project of Guile, and I want to do what I can to prevent
>> unnecessary friction.

> I appreciate the heads up you gave here today, but from our side, it
> doesn't seem like the Guile project is much concerned with our needs.
> The evaluation speed of GUILE 3.x is still pretty poor. Having fast,
> JIT'ed code seems interesting in theory, but the way it's implemented
> in Guile 3.x is a giant headache: the separate byte compilation is
> extremely slow, and it is hard to manage (where should the .go files
> be stored/installed, how/when are they generated etc.). It also
> doesn't match our use case, because a lot of the code that we have
> comes from .ly files, so it cannot be precompiled.

Are there ways to improve this? For example sticking to the baseline
compiler (as described in the wingolog:
https://wingolog.org/archives/2020/06/03/a-baseline-compiler-for-guile )

>> The article linked above shows that setting -O1 as optimization of the
>> code could help (if you’re not already doing that).

> The article gives a pointer to the code, which is
> module/language/tree-il/compile-bytecode.scm. I ran
> 
> for c in  $(git log module/language/tree-il/compile-bytecode.scm|grep
> commit|awk '{print $2;}'); do git show $c ; done | grep -i doc
> 
> to look for documentation, but couldn't find it. The module has one
> exported symbol, which is compile-bytecode.
> 
> Could you give some practical tips on how we'd use this?

Can someone help with this?

It would be pretty cool if there were a simple way to speed-up lilypond
like changing optimization level that just got lost in communication (or
missing docs).

Best wishes,
Arne
-- 
Unpolitisch sein
heißt politisch sein
ohne es zu merken

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