From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="TKw0O7f0" Received: from mail-oa1-x2c.google.com (mail-oa1-x2c.google.com [IPv6:2001:4860:4864:20::2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 769889C for ; Tue, 12 Dec 2023 17:18:43 -0800 (PST) Received: by mail-oa1-x2c.google.com with SMTP id 586e51a60fabf-1fb9a22b4a7so3801266fac.3 for ; Tue, 12 Dec 2023 17:18:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1702430323; x=1703035123; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=SjqGV1Kb/P5zbkrU4HZj42U242Y4ucdb6cKzFhJu16E=; b=TKw0O7f0+RjFtPX/EoJru2ueXfI3wGXJuk/UFASokbPUubJk+TWmZvm1U9PCvCjGFK rnXvaC+HPaLKdtFAdNyXL7jUWmob6gpbHef+9uZk2UmExJNwnuDxeITV/my6qedL/Y3Z vocryzYjOFH/UF4wLsou6Dw0QParbESABM42BdQwgcqGqO3mweeKdZTBb7R+Enrb+KQ4 pFY7S0guRKiN4ao0TfMrdrKuk7yapYIsVOOWIt4TjHrGXhosrZif5+/OLZ2y20OMzjYg UPv4pFjWuHpJzbilxw6loAolYVnw7d8GVTqZCTTUjj1tjBnTDufrp0k9XzD7l+07t/vK EATA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702430323; x=1703035123; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SjqGV1Kb/P5zbkrU4HZj42U242Y4ucdb6cKzFhJu16E=; b=NHDOFtd6EsNbRfUOpQ5vRCK5Q5+tfEU/IUuCbJwgM8z1PzuQLAu+bRPZseR6wbke4X ylLCVB5dVDTrwew+v4y/jXr5e48iTlFzq8LnvfHN1EOejQB8LgoO6Srcm8tnQSG2zRaS fZzlqaabcQ2QjME1VFNocxVzGWUVJDlKKAanfN2+/8lNFR8iQRQKHHnlmMsaZYwRcEqI Di8qLXIt1Vh6DN2T24rf7BShGFUumudRpK0mnivvrdHwFYkikhUFyVNJKSuHaogONGtJ bmp2nudMC2RvhDmhgobsWGQ+WZtXDKgFs+CzL1+0aSH3QjQb19UESU+UNADr1YAcM+cb m9dQ== X-Gm-Message-State: AOJu0Yym8KgsF8tz3ea2jlNNWjzhRW0oMmOP6QrmpVp/EDc9oR1JWcD9 MXxfokm1+HUO58muu1Cgq+JKpvD8tJHklhKDAzA= X-Google-Smtp-Source: AGHT+IGcpXKQDzSepggo4DA6an7sZ49nxOLPtoiybj/deuVMJvtLgMtNqZQ5vl9noZsHlO7zvyyAAA== X-Received: by 2002:a05:6870:7f03:b0:1fa:1f04:e5f1 with SMTP id xa3-20020a0568707f0300b001fa1f04e5f1mr8946584oab.34.1702430322830; Tue, 12 Dec 2023 17:18:42 -0800 (PST) Received: from charlie.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id cy26-20020a056830699a00b006d9a339773csm172548otb.27.2023.12.12.17.18.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Dec 2023 17:18:42 -0800 (PST) From: Charlie Jenkins Date: Tue, 12 Dec 2023 17:18:38 -0800 Subject: [PATCH v12 1/5] asm-generic: Improve csum_fold Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20231212-optimize_checksum-v12-1-419a4ba6d666@rivosinc.com> References: <20231212-optimize_checksum-v12-0-419a4ba6d666@rivosinc.com> In-Reply-To: <20231212-optimize_checksum-v12-0-419a4ba6d666@rivosinc.com> To: Charlie Jenkins , Palmer Dabbelt , Conor Dooley , Samuel Holland , David Laight , Xiao Wang , Evan Green , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Cc: Paul Walmsley , Albert Ou , Arnd Bergmann , David Laight X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1702430319; l=1517; i=charlie@rivosinc.com; s=20231120; h=from:subject:message-id; bh=FtbING0Tg9V1myoJvDDTr8ph0mEbsa+4mbxe/ijBRBI=; b=dJ5wOJMjymK/YpMtfR6jvWWktdU7txotFEvdWb2yuqaSvy9+MkF/Rz3ht0deRKm8zz0sRZ+ph Cz3UO09uQmsCFOG5spy3fV0k06pu9P/54kSRkrQ0X38OTK6yYmeYPna X-Developer-Key: i=charlie@rivosinc.com; a=ed25519; pk=t4RSWpMV1q5lf/NWIeR9z58bcje60/dbtxxmoSfBEcs= This csum_fold implementation introduced into arch/arc by Vineet Gupta is better than the default implementation on at least arc, x86, and riscv. Using GCC trunk and compiling non-inlined version, this implementation has 41.6667%, 25% fewer instructions on riscv64, x86-64 respectively with -O3 optimization. Most implmentations override this default in asm, but this should be more performant than all of those other implementations except for arm which has barrel shifting and sparc32 which has a carry flag. Signed-off-by: Charlie Jenkins Reviewed-by: David Laight --- include/asm-generic/checksum.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/checksum.h b/include/asm-generic/checksum.h index 43e18db89c14..ad928cce268b 100644 --- a/include/asm-generic/checksum.h +++ b/include/asm-generic/checksum.h @@ -2,6 +2,8 @@ #ifndef __ASM_GENERIC_CHECKSUM_H #define __ASM_GENERIC_CHECKSUM_H +#include + /* * computes the checksum of a memory block at buff, length len, * and adds in "sum" (32-bit) @@ -31,9 +33,7 @@ extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); static inline __sum16 csum_fold(__wsum csum) { u32 sum = (__force u32)csum; - sum = (sum & 0xffff) + (sum >> 16); - sum = (sum & 0xffff) + (sum >> 16); - return (__force __sum16)~sum; + return (__force __sum16)((~sum - ror32(sum, 16)) >> 16); } #endif -- 2.43.0