From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3ACF9D7236A for ; Fri, 23 Jan 2026 10:16:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pTO7ylh94o2uVWdNQ4bpRRPwEY8OTAPHBLEscsHjfQw=; b=OJAC8zjiy/xiae li7XSH6fdU16id72db6sgLeSUTSj4z0qDlmu+iGGlHBOq5Rw5bkFdm/HB2GRcpImg7TpLbB0Gd422 UhLB/G/EQQMdz9qlQ48q9uoPpSWFc8UtQIeErX0QFkin6DwZid3CBbN3fYI4aZLnZRYeGFQq5GnwQ hY9IzcIgDCwu8psoi4oKWu0uXghE8mRYX1rnJDDUpRNAu8oMZ/HDhHSqVRbXExi/IK+0Mjfvgolp7 oQarYfW7gKdG0VSFsS+AifM5EwKOLxGiEmlTW2BYDjmOIO3cUQCWVy5HtPce4tsRyq6sLCh7mKTt5 rRSGcvs8yw2m9N3wX0TA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vjED7-00000008hk0-2Ktz; Fri, 23 Jan 2026 10:16:13 +0000 Received: from mail-wm1-x336.google.com ([2a00:1450:4864:20::336]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vjED5-00000008hir-0Gel for linux-riscv@lists.infradead.org; Fri, 23 Jan 2026 10:16:12 +0000 Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-47edd9024b1so16704835e9.3 for ; Fri, 23 Jan 2026 02:16:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1769163369; x=1769768169; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=1766ltHWrMXyfFyRJgUmU5nLz/oknRF8EBvBBxM+APE=; b=WoXR6Nn1CAV5g4vw0JK6ZdQQIi42Rxp9PvxMQSNBPdyJkBdQLRhqqGpuE2UN6RT6D7 pPmUr1rikJC1f05Aewqyhsets4GbDSxqv4O/t0bDW3rE3pn0fJ68KHqjlmmYavI35F+Y zVCyqn3tMfnaAv2ymWtZPvlyxVHYTk4fJ9/BAqZidN8FGdLilzdFgFu++VUk24hGiJHl 6Tz98y+RaJQ5NFaTvI0UuOIJOnQPwM6HPlTV4GGSwpGGH0NC+7T6mWWhb5darzyHbvLk xO8L31Sf4Wurwsw6GAsgnchdBQFfuuodgeOjxe0CaLTA+tgOr9LsWRqoOom7kASO299Z eu7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769163369; x=1769768169; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=1766ltHWrMXyfFyRJgUmU5nLz/oknRF8EBvBBxM+APE=; b=ObLpWJefMMk1kwrz1pBtEGI66ivbVt3K4X5mk/EZNxjFaCav9guDmBB9UNpJ4Rx3zI cavhSeNCJDXx2K7MLMAfOjQ43EYMtY7GH/SxIfvbBBavuuT2hsWkMAQA2JG37EfOB9hR L531RoDcVEGlbo4KoQPEdD+OxCJsJTn/Ryq8UhGC/cTnJhyjRucTdFLDi8BsnK4VmePw UCQeD62rl/Y2HfbaW2gLXEMMCEohBWI0qpOg7Wi9zEuCp1vqJxo1hepQY/Ps5ywYtld6 ffiEHUjjk0OCUM2Opxo0ZUT/5Xi4nYEW6ad1wUvwkvHAb1WoZs/Dc4zoZ8hMqBVLez0i 5xag== X-Forwarded-Encrypted: i=1; AJvYcCX96Cm7BQGamAMZ4bRFVxv8ECvtIQSnIQQWW216KRxbzj2ZjPFLHcsyVXKomZe2YtHd1Qdu2dbgalk4cQ==@lists.infradead.org X-Gm-Message-State: AOJu0YxE+nDEmTF9KIlRUsWVtNL6iLiYriwt7ACTtTbI3sFQEwDZyjLw jY8jBP0ng+DHE64k68f8ckEACxWLqMH+B2IqCsJMxmdrMUMflNfriCKZ X-Gm-Gg: AZuq6aIP+wN/GXqeMdgnYj25H/WRYEsUqPX1/TvNNkPHzR5aMCgxa3T6N99m/CAx5kl IblkVE4BFw/a974wgKBbA/NtYtxhn3ozHxIIUJwvY2n+TnjsH/0sGVasxz7H9bv3c2AWlfvbJf+ d8dVMDAiIlGhst8Wb/dcwY06glgYxAYmWbUDDor7OsGzTTeeivTJHWwc65qEbgE4X3u5O5C7S1v 0JUMzS61EM34n/+u2uev+ViDmrN46wFYX2yii5CHAoXCdhk5KhLJhv0JAoQL6U34m9MFMO23Bf8 X5NDLbPI2w7xQ4vGaYdZ65QBF1Y7ujbCLTSgWpbDBVwacPv6BlLBWpMLQNjgLwjE7w0X2Is+yhu SXJV4ymbeNJ+Sk2GbHb8E8PXCa6bAqfUACn4JGURVy78WT3YjsSAZqvRLe4uAkqHqKxHnHnPf85 CUL6P3cTtENQFBIpAapFPweVJicpJnOCZ/8hVeSqJR2it1zOq/LOJ/LRRKNMSbtGk= X-Received: by 2002:a05:600c:620f:b0:47a:8088:439c with SMTP id 5b1f17b1804b1-4804c9d00f7mr44556815e9.35.1769163368531; Fri, 23 Jan 2026 02:16:08 -0800 (PST) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4804dbbb3c4sm16602415e9.13.2026.01.23.02.16.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Jan 2026 02:16:08 -0800 (PST) Date: Fri, 23 Jan 2026 10:16:02 +0000 From: David Laight To: Feng Jiang Cc: Andy Shevchenko , Andy Shevchenko , pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, akpm@linux-foundation.org, kees@kernel.org, andy@kernel.org, ebiggers@kernel.org, martin.petersen@oracle.com, ardb@kernel.org, charlie@rivosinc.com, conor.dooley@microchip.com, ajones@ventanamicro.com, linus.walleij@linaro.org, nathan@kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v3 0/8] riscv: optimize string functions and add kunit tests Message-ID: <20260123101602.111c6210@pumpkin> In-Reply-To: <26d08954-2826-4c48-a540-6e0857faf5ec@kylinos.cn> References: <20260120065852.166857-1-jiangfeng@kylinos.cn> <691a0183-6f41-4956-82da-abb69a449919@kylinos.cn> <20260121105717.04853c5d@pumpkin> <26d08954-2826-4c48-a540-6e0857faf5ec@kylinos.cn> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260123_021611_109462_3FA17F63 X-CRM114-Status: UNSURE ( 7.29 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Fri, 23 Jan 2026 11:12:00 +0800 Feng Jiang wrote: >... > I am still exploring some of the finer points of these low-level performance > trade-offs, so your input is very helpful. I will definitely spend some time > studying this further and experiment with the approaches you mentioned. You can spend a long time micro-optimising small functions. I know, I've done it.... Then you need to test on as many cpu variants as you can find. David _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv