long-shot feature request: elixir OTP 25 builds with JIT disabled

[Santiago Bernhardt]

something on the line of:

• 1.14.2-erlang-24.3.4.9-debian-bullseye-20230202-slim-nojit
• x.x.x-erlang-25.x.x-distro-something-somethingelse-nojit

[Eric Meadows-Jönsson]

What's the use case for this?

[Santiago Bernhardt]

Been running dockerfiles with

ENV ERL_COMPILER_OPTIONS="[{d,'JIT_INFO',false}]"

to avoid segmentation faults in arm64 builds but would be ideal to have it image specific instead of dockerfile tuned.

[Eric Meadows-Jönsson]

You can select a different emulator with -emu_flavor. https://www.erlang.org/doc/man/erl.html

Since there are options to disable the JIT I don't feel like separate images are needed since it would double the amount we have to build.

[Santiago Bernhardt]

Makes sense, thanks for clarifying.

[Wojtek Mach]

From aforementioned docs:

(The emulator with this flavor must be built. You can build a specific flavor by doing make FLAVOR=$FLAVOR in the Erlang/OTP source repository.)

are we building our images with make FLAVOR=? If not then -emu_flavour flag will only be useful with the default value, smp. If we aren't I think maybe we should, I'm not aware of downsides of doing so.

[José Valim]

The downside is larger images. The beam flavor is slower and likely only to get slower with time, I would avoid it the most we can.

[ruslandoga]

Sorry to post in a closed issue but what is the recommended way to disable JIT in the current hexpm images?

I've tried the following options:

• ENV ERL_FLAGS="+JPperf true" doesn't disable JIT but the build works
• ENV ERL_COMPILER_OPTIONS="[{d,'JIT_INFO',false}]" doesn't work
• ENV ERL_FLAGS="-emu_flavor smp" doesn't work
• ENV ELIXIR_ERL_OPTIONS="-emu_flavor smp" doesn't work

Reference build: ruslandoga/plausible#93

[José Valim]

No, it is not possible. The VM is compiled with the JIT in.

[ruslandoga]

I see. Thank you!