vchiq: Performance regression since 5.18-rc1

[Marcelo Tosatti]

On Mon, May 23, 2022 at 09:09:07AM +0200, Sebastian Andrzej Siewior wrote:
> On 2022-05-22 01:22:00 [+0200], Stefan Wahren wrote:
> > Hi,
> Hi,
> 
> > while testing the staging/vc04_services/interface/vchiq_arm driver with my
> > Raspberry Pi 3 B+ (multi_v7_defconfig) i noticed a huge performance
> > regression since [ff042f4a9b050895a42cae893cc01fa2ca81b95c] mm:
> > lru_cache_disable: replace work queue synchronization with synchronize_rcu
> > 
> > Usually i run "vchiq_test -f 1" to see the driver is still working [1].
> 
> What about
> 	https://lore.kernel.org/all/YmrWK%2FKoU1zrAxPI@fuller.cnet/
> 
> Sebastian

Stefan,

Can you please try the patch above ?