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[v3,5/5] crypto: lib/sha256 - Unroll LOAD and BLEND loops

Message ID 20201023192203.400040-6-nivedita@alum.mit.edu
State Superseded
Headers show
Series [v3,1/5] crypto: Use memzero_explicit() for clearing state | expand

Commit Message

Arvind Sankar Oct. 23, 2020, 7:22 p.m. UTC 
Unrolling the LOAD and BLEND loops improves performance by ~8% on x86_64
(tested on Broadwell Xeon) while not increasing code size too much.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
---
 lib/crypto/sha256.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)
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Patch

diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
index e2e29d9b0ccd..cdef37c05972 100644
--- a/lib/crypto/sha256.c
+++ b/lib/crypto/sha256.c
@@ -76,12 +76,28 @@  static void sha256_transform(u32 *state, const u8 *input, u32 *W)
 	int i;
 
 	/* load the input */
-	for (i = 0; i < 16; i++)
-		LOAD_OP(i, W, input);
+	for (i = 0; i < 16; i += 8) {
+		LOAD_OP(i + 0, W, input);
+		LOAD_OP(i + 1, W, input);
+		LOAD_OP(i + 2, W, input);
+		LOAD_OP(i + 3, W, input);
+		LOAD_OP(i + 4, W, input);
+		LOAD_OP(i + 5, W, input);
+		LOAD_OP(i + 6, W, input);
+		LOAD_OP(i + 7, W, input);
+	}
 
 	/* now blend */
-	for (i = 16; i < 64; i++)
-		BLEND_OP(i, W);
+	for (i = 16; i < 64; i += 8) {
+		BLEND_OP(i + 0, W);
+		BLEND_OP(i + 1, W);
+		BLEND_OP(i + 2, W);
+		BLEND_OP(i + 3, W);
+		BLEND_OP(i + 4, W);
+		BLEND_OP(i + 5, W);
+		BLEND_OP(i + 6, W);
+		BLEND_OP(i + 7, W);
+	}
 
 	/* load the state into our registers */
 	a = state[0];  b = state[1];  c = state[2];  d = state[3];