[asa400]

Just a data point on the deps compilation, on a small Phoenix app with mostly stock Phoenix deps:

  MIX_OS_DEPS_COMPILE_PARTITION_COUNT=1 mix deps.compile  32.30s user 7.23s system 320% cpu 12.336 total

  MIX_OS_DEPS_COMPILE_PARTITION_COUNT=5 mix deps.compile  0.37s user 0.49s system 12% cpu 6.970 total

  MIX_OS_DEPS_COMPILE_PARTITION_COUNT=10 mix deps.compile  0.38s user 0.50s system 12% cpu 7.236 total

Machine is a Mac M1 Max, `rm -rf _build` in between each run.

[yuliyp]

You're measuring a cached compile in the subsequent runs. The deps.compile probably did some native compilation in the dep folder directly rather in _build.

[dns_snek]

No their results are correct. It roughly halved the compilation time on a newly generated Phoenix project. I'm assuming the savings would be more extensive on projects with multiple native dependencies that have lengthy compilation.

    rm -rf _build/ deps/ && mix deps.get && time MIX_OS_DEPS_COMPILE_PARTITION_COUNT=1 mix deps.compile
    ________________________________________________________
    Executed in   37.75 secs    fish           external
       usr time  103.65 secs   32.00 micros  103.65 secs
       sys time   20.14 secs  999.00 micros   20.14 secs

    rm -rf _build/ deps/ && mix deps.get && time MIX_OS_DEPS_COMPILE_PARTITION_COUNT=5 mix deps.compile
    ________________________________________________________
    Executed in   16.71 secs    fish           external
       usr time    2.39 secs    0.05 millis    2.39 secs
       sys time    0.87 secs    1.01 millis    0.87 secs
    
    rm -rf _build/ deps/ && mix deps.get && time MIX_OS_DEPS_COMPILE_PARTITION_COUNT=10 mix deps.compile
    ________________________________________________________
    Executed in   17.19 secs    fish           external
       usr time    2.41 secs    1.09 millis    2.40 secs
       sys time    0.89 secs    0.04 millis    0.89 secs

[dns_snek]

Similar result on one of my real projects that's heavier on the Elixir dependencies but that only has 1 additional native dependency (brotli):

    mise use elixir@1.19-otp-26 erlang@26
    
    rm -rf _build/ deps/ && mix deps.get && time MIX_OS_DEPS_COMPILE_PARTITION_COUNT=1 mix deps.compile
    ________________________________________________________
    Executed in   97.93 secs    fish           external
       usr time  149.37 secs    1.45 millis  149.37 secs
       sys time   28.94 secs    1.11 millis   28.94 secs
    
    rm -rf _build/ deps/ && mix deps.get && time MIX_OS_DEPS_COMPILE_PARTITION_COUNT=5 mix deps.compile
    ________________________________________________________
    Executed in   42.19 secs    fish           external
       usr time    2.48 secs    0.77 millis    2.48 secs
       sys time    0.91 secs    1.21 millis    0.91 secs

[yuliyp]

Oh, interesting. I guess `time` is only reporting the usr/sys time of the main process rather than the child workers when using PARTITION_COUNT higher than 1?

[asa400]

Anyone downvoting care to comment on why a benchmark of a feature in this release is downvote worthy?