Re: regression: gpiolib: switch the line state notifier to atomic unexpected impact on performance

[Kent Gibson]

On Tue, Mar 11, 2025 at 12:03:46PM +0100, David Jander wrote:
>
>
> Indeed, it does. My application is written in python and uses the python gpiod
> module. Even in such an environment the impact is killing.
>

Interesting - the only reason I could think of for an application
requesting/releasing GPIOs at a high rate was it if was built on top of
the libgpiod tools and so was unable to hold the request fd.
Generally an application should request the lines it requires once and hold
them for the duration.  Similarly functions such as find_line() should be
performed once per line.
>From a performance perspective, NOT having to re-request a line is
considerably faster than requesting it - even with Bart's fix.

Is there something unusual about your app that requires the lines be
released?

Cheers,
Kent.