Change default method of disabling JIT for PHP 8.4

Hello Daniil,
I like this proposition. I never understood why the JIT is disabled by the
ini setting buffer_size rather than other simple 'switch' like setting.

Kind regards,
Jorg

Am 17.10.2023 um 19:46 schrieb Daniil Gentili daniil@daniil.it:

I would like to submit an RFC and PR to change a few INI defaults for opcache, changing how JIT is disabled by default.

Currently, JIT is disabled by default using the |opcache.jit_buffer_size=0| default, instead of |opcache.jit=0|.

I would like to change these defaults to:

• opcache.jit=off
• opcache.jit_buffer_size=64m (taken from https://github.com/php/php-src/pull/12425/files, any smaller multiple of 2 causes the buffer to fill up when running moderately sized projects like Psalm or PHPStan).

I understand your point but it might unexpectedly switch behavior for people just setting jit_buffer_size and expecting this to turn JIT on.
While (in the light of a new upcoming JIT) this might not be a big deal it is also not clear if it is worth it.
Maybe the settings can be overhauled once the new JIT is introduced (which might have different settings anyway).

Regards,

• Chris

Hello,

I would like to submit an RFC and PR to change a few INI defaults for
opcache, changing how JIT is disabled by default.

Currently, JIT is disabled by default using the
|opcache.jit_buffer_size=0| default, instead of |opcache.jit=0|.

I.e. here are the defaults for these two configuration entries:

• opcache.jit=tracing
• opcache.jit_buffer_size=0

This effectively disables JIT not because jit=0, but rather because
the buffer size is set to 0.

I would like to change these defaults to:

• opcache.jit=off
• opcache.jit_buffer_size=64m (taken from
  https://github.com/php/php-src/pull/12425/files, any smaller multiple of
  2 causes the buffer to fill up when running moderately sized projects
  like Psalm or PHPStan).

What do you think?

Actually, now opcache.jit=0/off/no/false doesn't disable JIT completely. It
makes PHP start requests with JIT disabled, but this may be changed during
the request.
JIT may be disabled completely by opcache.jit=disable

Thanks. Dmitry.

Kind regards,

Daniil Gentili.

Hi all, I've created the actual RFC:
https://wiki.php.net/rfc/jit_config_defaults

Regards,

Daniil Gentili.