Page MenuHomeFreeBSD

powerpc64: make radix with superpages default
ClosedPublic

Authored by luporl on Jun 17 2021, 11:20 AM.

Details

Summary

As Radix MMU with superpages enabled is now stable, make it the
default choice on supported hardware (POWER9 and above), since its
performance is greater than that of HPT MMU.

Test Plan

Tested on POWER8 and POWER9 VMs and physical machines.

Diff Detail

Repository
R10 FreeBSD src repository
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

This revision is now accepted and ready to land.Jun 17 2021, 4:49 PM
alfredo requested changes to this revision.Jun 17 2021, 7:58 PM

For some reason this breaks the boot with VGA console on Blackbird.
I'm using D30626 locally, but reverted it as well. With D30626 reverted and adding kernel parameter 'hw.ofwfb.physaddr=0x000600c280000000' the kernel hangs as well with no output.

Works:
'hw.ofwfb.physaddr=0x000600c280000000 radix_mmu=0 vm.pmap.superpages_enabled=0'
'hw.ofwfb.physaddr=0x000600c280000000 radix_mmu=0 vm.pmap.superpages_enabled=1'

Doesn't work:
'hw.ofwfb.physaddr=0x000600c280000000 radix_mmu=1 vm.pmap.superpages_enabled=0'
'hw.ofwfb.physaddr=0x000600c280000000 radix_mmu=1 vm.pmap.superpages_enabled=1'

It seems like superpages doesn't hurt, but something must be changed in ofwfb to work with radix_mmu

This revision now requires changes to proceed.Jun 17 2021, 7:58 PM

D31232 fixes OFWFB with radix. After it lands it should be safe to make radix default.

I tested this patch with D31232 few weeks ago on the Blackbird and it looks good to me once it's approved.

This revision is now accepted and ready to land.Sep 15 2021, 3:05 PM