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 X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3974C49EA6 for ; Sun, 27 Jun 2021 03:44:59 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 78D4261A36 for ; Sun, 27 Jun 2021 03:44:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78D4261A36 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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:Date:Subject:To:From:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=eWhyYhnARpvoau4CiCwRZWGHiAsrtzvJkbiu3v7bLRc=; b=kD98PHxv/yN6Le 3xb12OdIpc4HmPqplbGpGqSyYA0ZsMhrqHj17RowCm9jj+Jq+ye35PJlWE7ZTB5E2HCXG1sGyZBWb DNKsZFiomSw7btrn28cM8JDtwvqXDyJn1kTIbXP9rttiluhJst4JI3bDi2hxCjcs/C3/i7qw7OXTP Dh0yOhBZeXmu6kWafRBogG09YxHad201AJj3U8JAfk5opSTWYi0/OWhNzsLxZS46XEHL/2Zn6SkSM LIj12XxHScK2ph4SmwRr0c9Vf9L6B6wXCYCke4wZ2kDoztvzBhCyBcbzmyaWaRQgtXhzNzfUXRWe5 +VwT/gJeaV3vDk7UjPzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lxLil-0054rv-Qh; Sun, 27 Jun 2021 03:44:35 +0000 Received: from mail-pj1-x1034.google.com ([2607:f8b0:4864:20::1034]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lxLii-0054rd-UY for linux-riscv@lists.infradead.org; Sun, 27 Jun 2021 03:44:34 +0000 Received: by mail-pj1-x1034.google.com with SMTP id z3-20020a17090a3983b029016bc232e40bso8043591pjb.4 for ; Sat, 26 Jun 2021 20:44:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:organization:in-reply-to:references :mime-version:content-transfer-encoding; bh=VG8S046SmOK6XAcmQMtK1F0n3FEUbqWr84n7cjWYyUU=; b=DGNttt4tcvVtIhc0NKCshka7OiKtnQzfOFY2MCTjzPsGwB66pO2UzDbxDn+JNhMyMc 1V5CHUzaE14aZyEalra0HbRsMxDshQSBAw2+fV+TaVf9G8p/h+N8EDyxZ/iMAZbspD5j c7xhLNWQhL4+Af2uK97KQFdXD99UcEmB2k0mtokocyGQJFwU+TX78FMKa5rM15woVr/Q Pn3oe3j0lcW8GJ7Ze3r+qVb55Av9VqLw5UC6DJ083UjUBDUydvbV/y7m0VwlZuWWJW73 7tx3fgLkSUx8Ab/RftQnwQ4bc5bQFlvmYTFFwFXC1zCjs+4zlZUlvr8MiuOb39JbyOO+ mMCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:organization :in-reply-to:references:mime-version:content-transfer-encoding; bh=VG8S046SmOK6XAcmQMtK1F0n3FEUbqWr84n7cjWYyUU=; b=meql8G9FYA9JeaLXgDfFGhKbLHk2Kgnj9qLbidhPHEjrF/Suw+jVxG0sBe464hznUG gKr8ccLur7HIdiRXPqMLi1EjDD5/baHHR89ZNrWwkg7CVDJPMtqsfRwaCbm2y3bDtL1w /KSsDx+kbczaodOZqSMaI2+x4NZApZrXPO0gw8HGDS73a7L3kNctgUyg5C75LTssXq1Z hE+cFod/3C8twd+Jlcn2eNYI5re0y5Yv1n0oV0D6ubV71ij0APtnNAF1upmIx4+ehi1l DPHap00BiibU2FD3YKJWFwC5vmwgz5/kaXdSu/VAf/EjachAtPdTEV61xjiG+s2I8lT2 U9Ag== X-Gm-Message-State: AOAM530p+2v1s/NGwFsAf8lnY7NS9+/XlmWCPvk5Mo21ArYuZHLENYo3 XSErFYk/TlKtnEWpV3YqGN840/+EnnSBLA== X-Google-Smtp-Source: ABdhPJz6Bqdjt7zeRSJlRmj/IOvQDURasPuJJPRLQaGCXZdTrOsayKJyAVXqDsqyQi8dxIBFW8Twjg== X-Received: by 2002:a17:90b:1102:: with SMTP id gi2mr30170290pjb.75.1624765471825; Sat, 26 Jun 2021 20:44:31 -0700 (PDT) Received: from rata.localnet (fred.taniwha.com. [203.86.204.69]) by smtp.gmail.com with ESMTPSA id z3sm9808890pfa.67.2021.06.26.20.44.30 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Jun 2021 20:44:31 -0700 (PDT) From: Paul Campbell To: linux-riscv@lists.infradead.org Subject: Re: prefetchw() Date: Sun, 27 Jun 2021 15:44:28 +1200 Message-ID: <2035172.PIDvDuAF1L@rata> Organization: Moonbase Otago In-Reply-To: <2623321.7s5MMGUR32@rata> References: <2623321.7s5MMGUR32@rata> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210626_204433_053562_BB76485D X-CRM114-Status: UNSURE ( 8.96 ) 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 Sunday, 27 June 2021 3:31:18 PM NZST Paul Campbell wrote: > i noticed today that __builtin_prefetch() emits nothing (at least in my gcc) > > i wonder if it makes sense to do this for riscv linux? > > static inline void prefetchw( volatile void *addr) > { > asm volatile("lb x0, 0(%0)" : : "r" (addr)); > } I should add that gcc __builtin_prefetch() promises not to fault while the kernel prefetchw(), from my quick look through the code doesn't seem to depend on that (in fact loops get unrolled in places to make sure) Paul _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv