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authorDirk Müller <dmueller@suse.de>2022-01-05 17:38:47 +0100
committerSong Liu <song@kernel.org>2022-01-06 08:37:03 -0800
commit36dacddbf0bdba86cd00f066b4d724157eeb63f1 (patch)
tree3875efa25f6b1115f386c5d9d2805e0f732ce7a0
parent38640c480939d56cc8b03d58642fc5261761a697 (diff)
lib/raid6: Use strict priority ranking for pq gen() benchmarking
On x86_64, currently 3 variants of AVX512, 3 variants of AVX2 and 3 variants of SSE2 are benchmarked on initialization, taking between 144-153 jiffies. Testing across a hardware pool of various generations of intel cpus I could not find a single case where SSE2 won over AVX2 or AVX512. There are cases where AVX2 wins over AVX512 however. Change "prefer" into an integer priority field (similar to how recov selection works) to have more than one ranking level available, which is backwards compatible with existing behavior. Give AVX2/512 variants higher priority over SSE2 in order to skip SSE testing when AVX is available. in a AVX2/x86_64/HZ=250 case this saves in the order of 200ms of initialization time. Signed-off-by: Dirk Müller <dmueller@suse.de> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Song Liu <song@kernel.org>
-rw-r--r--include/linux/raid/pq.h2
-rw-r--r--lib/raid6/algos.c2
-rw-r--r--lib/raid6/avx2.c8
-rw-r--r--lib/raid6/avx512.c6
4 files changed, 9 insertions, 9 deletions
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 154e954b711d..d6e5a1feb947 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -81,7 +81,7 @@ struct raid6_calls {
void (*xor_syndrome)(int, int, int, size_t, void **);
int (*valid)(void); /* Returns 1 if this routine set is usable */
const char *name; /* Name of this routine set */
- int prefer; /* Has special performance attribute */
+ int priority; /* Relative priority ranking if non-zero */
};
/* Selected algorithm */
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 9b7e8a837b27..39b74221f4a7 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -151,7 +151,7 @@ static inline const struct raid6_calls *raid6_choose_gen(
const struct raid6_calls *best;
for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
- if (!best || (*algo)->prefer >= best->prefer) {
+ if (!best || (*algo)->priority >= best->priority) {
if ((*algo)->valid && !(*algo)->valid())
continue;
diff --git a/lib/raid6/avx2.c b/lib/raid6/avx2.c
index f299476e1d76..059024234dce 100644
--- a/lib/raid6/avx2.c
+++ b/lib/raid6/avx2.c
@@ -132,7 +132,7 @@ const struct raid6_calls raid6_avx2x1 = {
raid6_avx21_xor_syndrome,
raid6_have_avx2,
"avx2x1",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX2 over priority 1 (SSE2 and others) */
};
/*
@@ -262,7 +262,7 @@ const struct raid6_calls raid6_avx2x2 = {
raid6_avx22_xor_syndrome,
raid6_have_avx2,
"avx2x2",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX2 over priority 1 (SSE2 and others) */
};
#ifdef CONFIG_X86_64
@@ -465,6 +465,6 @@ const struct raid6_calls raid6_avx2x4 = {
raid6_avx24_xor_syndrome,
raid6_have_avx2,
"avx2x4",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX2 over priority 1 (SSE2 and others) */
};
-#endif
+#endif /* CONFIG_X86_64 */
diff --git a/lib/raid6/avx512.c b/lib/raid6/avx512.c
index bb684d144ee2..9c3e822e1adf 100644
--- a/lib/raid6/avx512.c
+++ b/lib/raid6/avx512.c
@@ -162,7 +162,7 @@ const struct raid6_calls raid6_avx512x1 = {
raid6_avx5121_xor_syndrome,
raid6_have_avx512,
"avx512x1",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX512 over priority 1 (SSE2 and others) */
};
/*
@@ -319,7 +319,7 @@ const struct raid6_calls raid6_avx512x2 = {
raid6_avx5122_xor_syndrome,
raid6_have_avx512,
"avx512x2",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX512 over priority 1 (SSE2 and others) */
};
#ifdef CONFIG_X86_64
@@ -557,7 +557,7 @@ const struct raid6_calls raid6_avx512x4 = {
raid6_avx5124_xor_syndrome,
raid6_have_avx512,
"avx512x4",
- 1 /* Has cache hints */
+ .priority = 2 /* Prefer AVX512 over priority 1 (SSE2 and others) */
};
#endif