powerpc/64s/idle: Avoid SRR usage in idle sleep/wake paths

Browse source

Idle code now always runs at the 0xc... effective address whether
in real or virtual mode. This means rfid can be ditched, along
with a lot of SRR manipulations.

In the wakeup path, carry SRR1 around in r12. Use mtmsrd to change
MSR states as required.

This also balances the return prediction for the idle call, by
doing blr rather than rfid to return to the idle caller.

On POWER9, 2-process context switch on different cores, with snooze
disabled, increases performance by 2%.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Incorporate v2 fixes from Nick]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

...

This commit is contained in:

Nicholas Piggin 2017-06-13 23:05:51 +10:00 • committed by Michael Ellerman

parent b51351e264

commit 9d29250136

3 changed files with 38 additions and 32 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

1

arch/powerpc/kernel/exceptions-64s.S

View file

57

arch/powerpc/kernel/idle_book3s.S

View file

12

arch/powerpc/kvm/book3s_hv_rmhandlers.S

View file