diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2018-02-22 23:35:45 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-25 11:05:50 +0100 |
| commit | ec0084d082137b73460303b39f4089970a213ad7 (patch) | |
| tree | 42bde0bfad3a8a0ff28a05795fd853f92bed756b /arch/powerpc/include | |
| parent | efe8bc07c47fff196bbc0822e249a27ae0574d24 (diff) | |
powerpc/64s: Improve RFI L1-D cache flush fallback
commit bdcb1aefc5b3f7d0f1dc8b02673602bca2ff7a4b upstream.
The fallback RFI flush is used when firmware does not provide a way
to flush the cache. It's a "displacement flush" that evicts useful
data by displacing it with an uninteresting buffer.
The flush has to take care to work with implementation specific cache
replacment policies, so the recipe has been in flux. The initial
slow but conservative approach is to touch all lines of a congruence
class, with dependencies between each load. It has since been
determined that a linear pattern of loads without dependencies is
sufficient, and is significantly faster.
Measuring the speed of a null syscall with RFI fallback flush enabled
gives the relative improvement:
P8 - 1.83x
P9 - 1.75x
The flush also becomes simpler and more adaptable to different cache
geometries.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Backport to 4.9]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index ea43897183fd..c75ee2d886fc 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -212,8 +212,7 @@ struct paca_struct { */ u64 exrfi[13] __aligned(0x80); void *rfi_flush_fallback_area; - u64 l1d_flush_congruence; - u64 l1d_flush_sets; + u64 l1d_flush_size; #endif }; |