Re: GUILE 2/3 and string encoding cost

[Han-Wen Nienhuys]

On Wed, Jan 22, 2020 at 10:53 PM Han-Wen Nienhuys <address@hidden> wrote:

> The GUILE 2.0 release
>
>   https://lwn.net/Articles/428288/
>
> has one big red flag for me.
>
>   * Switch to the Boehm-Demers-Weiser garbage collector
>

We can easily measure this, by adding the following to

#(display (version))
#(display " gc time taken: ")
#(display (* 1.0 (/ (cdr (assoc 'gc-time-taken (gc-stats)))
internal-time-units-per-second)))
#(display "\n")

on mozart-hrn-3, over 3 runs, we get

2.0.14  - avg 2.1s
1.8.8 - avg 0.31s

so the new GC is about 5-10x slower than the old one. With GUILE 1.8,
garbage collection covers typically is 10% of the runtime, so all things
equal, the Boehm GC would cause a 1.5-2.0x slowdown in the total.

It would be good to see how the JITting of code impacts Scheme execution.

-- 
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen