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| author | Nicholas Piggin <npiggin@gmail.com> | 2018-01-17 16:58:18 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-23 08:16:33 +0300 |
| commit | bdcb1aefc5b3f7d0f1dc8b02673602bca2ff7a4b (patch) | |
| tree | 28cdc8c18891bc84f17877cfc3ed1c3dbf7b197f /arch/powerpc/xmon | |
| parent | 35adacd6fc48d658419522f192a3c8b2785612da (diff) | |
| download | linux-bdcb1aefc5b3f7d0f1dc8b02673602bca2ff7a4b.tar.xz | |
powerpc/64s: Improve RFI L1-D cache flush fallback
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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/xmon')
| -rw-r--r-- | arch/powerpc/xmon/xmon.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 01d9a2dcff20..82e1a3ee6e0f 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -2377,8 +2377,6 @@ static void dump_one_paca(int cpu) printf(" slb_cache[%d]: = 0x%016lx\n", i, p->slb_cache[i]); DUMP(p, rfi_flush_fallback_area, "px"); - DUMP(p, l1d_flush_congruence, "llx"); - DUMP(p, l1d_flush_sets, "llx"); #endif DUMP(p, dscr_default, "llx"); #ifdef CONFIG_PPC_BOOK3E |