crypto: lib/sha256 - Unroll LOAD and BLEND loops

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>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Arvind Sankar 2020-10-25 10:31:19 -04:00 committed by Herbert Xu
parent 63642d5c14
commit 18d05ca448

View File

@ -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];