ORC support for arm64, and compositor performance

[Mart Raudsepp]

Ühel kenal päeval, T, 08.02.2022 kell 09:20, kirjutas David Ing via
gstreamer-devel:
> Mart,
> 
> I am curious:  What is the highest version of gstreamer that you
> observed this crash with?

It was back in March 2021 with GStreamer 1.18.4 and ORC git master at
the time.
There have been not many changes to ORC since then, but there is a
loadoff{b,w,l} commit that was done for performance reasons, so who
knows, maybe it helps.

> Also:  It sounds like you verified it was definitely ORC by disabling
> those optimizations, and running without a crash.  Is that correct?

The crash was there only after ORC was updated from 0.4.32 to git from
March 2021 state, otherwise it seemed to work. But due to being orders
of magnitude slower, it wasn't able to keep up in performance with the
live pipeline, so triggered other issues.

The crash backtrace pointed squarely at the new ORC code really.
It wasn't an instant crash on the first frame, as far as I recall, but
something that happened quite some time into the pipelines runtime.

I feel quite bad for not having saved the backtrace and following up on
it, but I thought I will with a more thorough analysis, but ended up
having to quickly move back to x86_64 instead and it was left on the
sidelines.

So really, just take it as a warning to test thoroughly for your use
cases and that's all.


Mart