From: Jussi Kivilinna Subject: [PATCH 3/3] crypto: arc4: improve performance by using u32 for ctx and variables Date: Sat, 09 Jun 2012 18:25:46 +0300 Message-ID: <20120609152546.16420.95998.stgit@localhost6.localdomain6> References: <20120609152535.16420.13917.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Jon Oberheide , Herbert Xu , "David S. Miller" To: linux-crypto@vger.kernel.org Return-path: Received: from sd-mail-sa-02.sanoma.fi ([158.127.18.162]:37512 "EHLO sd-mail-sa-02.sanoma.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260Ab2FIPZs (ORCPT ); Sat, 9 Jun 2012 11:25:48 -0400 In-Reply-To: <20120609152535.16420.13917.stgit@localhost6.localdomain6> Sender: linux-crypto-owner@vger.kernel.org List-ID: This patch changes u8 in struct arc4_ctx and variables to u32 (as AMD seems to have problem with u8 array). Below are tcrypt results of old 1-byte block cipher versus ecb(arc4) with u8 and ecb(arc4) with u32. tcrypt results, x86-64 (speed ratios: new-u32/old, new-u8/old): u32 u8 AMD Phenom II : x3.6 x2.7 Intel Core 2 : x2.0 x1.9 tcrypt results, i386 (speed ratios: new-u32/old, new-u8/old): u32 u8 Intel Atom N260 : x1.5 x1.4 Cc: Jon Oberheide Signed-off-by: Jussi Kivilinna --- crypto/arc4.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/crypto/arc4.c b/crypto/arc4.c index 07913fc..5a772c3 100644 --- a/crypto/arc4.c +++ b/crypto/arc4.c @@ -22,8 +22,8 @@ #define ARC4_BLOCK_SIZE 1 struct arc4_ctx { - u8 S[256]; - u8 x, y; + u32 S[256]; + u32 x, y; }; static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key, @@ -39,7 +39,7 @@ static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key, ctx->S[i] = i; for (i = 0; i < 256; i++) { - u8 a = ctx->S[i]; + u32 a = ctx->S[i]; j = (j + in_key[k] + a) & 0xff; ctx->S[i] = ctx->S[j]; ctx->S[j] = a; @@ -53,9 +53,9 @@ static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key, static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, unsigned int len) { - u8 *const S = ctx->S; - u8 x, y, a, b; - u8 ty, ta, tb; + u32 *const S = ctx->S; + u32 x, y, a, b; + u32 ty, ta, tb; if (len == 0) return;