[EduardoRFS]

OCaml is really good at building in parallel. So even without that many files it can still compile using 32 threads.

Making so that a project with 20k loc is less than a second in debug mode. And recompile time in native(debug) mode is almost 100% linking time.

For bytecode you can have wild rebuild times, in the milisecond range.

[fnord123]

Pyre[1] is about 20k loc of ocaml[2].

    $ time make -C source -j8
    make: Entering directory '/home/fnord123/src/download/pyre-check/source'
    ../scripts/setup.sh --configure
    Build info: Linux x86_64 @ Mon Aug 23 2021 (development build)
    abort: no repository found in '/home/fnord123/src/download/pyre-check/source' (.hg not found)!
    Git commit: 1e4dd5a39db1631fd13a3a8df74d6e0f5d801fbc
    dune build @install -j auto --profile dev
           menhir parser/generator.{ml,mli}
    Warning: 31 states have shift/reduce conflicts.
    Warning: 5 states have reduce/reduce conflicts.
    Warning: 77 shift/reduce conflicts were arbitrarily resolved.
    Warning: 75 reduce/reduce conflicts were arbitrarily resolved.
    make: Leaving directory '/home/fnord123/src/download/pyre-check/source'

    real 0m43.700s
    user 4m3.030s
    sys 0m41.005s

I must be doing something wrong.

[1] https://github.com/facebook/pyre-check [2]

    $ tokei
    -------------------------------------------------------------------------------
     Language            Files        Lines         Code     Comments       Blanks
    -------------------------------------------------------------------------------
     Autoconf                2          235          204            3           28
     C                      15       242641       165361        60669        16611
     C Header               10        14267         2617        11094          556
     Coq                    10         2391         1968          220          203
     CSS                     5          713          540           44          129
     Dockerfile              2           71           42           11           18
     HTML                    2           35           30            0            5
     INI                     1           12            9            0            3
     Java                   31         2654         2080          267          307
     JavaScript              7          867          752           61           54
     JSON                   17          939          939            0            0
     Makefile                5          229          145           45           39
     Markdown               47         7213         7213            0            0
     OCaml                 791       229096       198302        10455        20339
     Python                398        61909        50119         2917         8873
     Shell                   5          111           59           34           18
     SVG                     2            2            2            0            0
     TeX                     4          929          642          129          158
     Plain Text              5          457          457            0            0
     TOML                    1            2            2            0            0
     TypeScript              2          130           84           20           26
    -------------------------------------------------------------------------------
     Total                1362       564903       431567        85969        47367
    -------------------------------------------------------------------------------

[Jtsummers]

> Pyre[1] is about 20k loc of ocaml[2].

Reading your table, there are 198302 lines of OCaml code. That's about 10x larger than the 20k you claim. The 20339 in that row is the count of blank lines. I doubt they matter much here.