Boots and seems to work with PREEMPT enabled

[Anton Ivanov]

On 20/09/2023 12:14, Anton Ivanov wrote:
> Added support for kernel side fpu store/restore and real kernel_fpu_begin/kernel_fpu_end using gcc intrinsics. Enabled PREEMPT.
> 
> It boots and seems to be alive and kicking. I do not notice any significant effect on performance either.
> 

I take my words back - I was testing with VOLUNTARY which seems to provide a difference withing the margin of error.

Enabling forced preemption drops the time for

find /usr -type f -exec cat {} > /dev/null \;

from

real	19m11.207s
user	0m0.180s
sys	2m41.160s

to

real	3m13.647s
user	0m0.000s
sys	2m58.270s

And boot time from 11.5s to 6s.

It did complain on shutdown though with some traces. Nothing while running.

The patch will hit the mailing list shortly.


> How do I test it from here onwards?

The question still stands. Can we use anything as a specific test suite? It is not an area I am familiar with, so any pointers will be welcome.

> 
> I am happy to throw the patches on the list as an RFC, though I would prefer to test first :)
> 

-- 
Anton R. Ivanov
https://www.kot-begemot.co.uk/