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=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 26AC5C433DF for ; Sat, 15 Aug 2020 15:03:13 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 DF46E22DCC for ; Sat, 15 Aug 2020 15:03:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="tY8QGWDc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF46E22DCC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:32936 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k6xiC-0005fn-4c for qemu-devel@archiver.kernel.org; Sat, 15 Aug 2020 11:03:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45054) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k6xed-0002Gm-VF for qemu-devel@nongnu.org; Sat, 15 Aug 2020 10:59:31 -0400 Received: from mail-pf1-x42d.google.com ([2607:f8b0:4864:20::42d]:45065) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1k6xec-0005br-0h for qemu-devel@nongnu.org; Sat, 15 Aug 2020 10:59:31 -0400 Received: by mail-pf1-x42d.google.com with SMTP id f193so5946388pfa.12 for ; Sat, 15 Aug 2020 07:59:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=FI/r/KPM3NamuEvu+F9mW+RliiWbhgVxKmNTvx6BQcc=; b=tY8QGWDcFtWOVpQJZV0liCOS04JLlmA+FB8vkBPVaUAkjzJWRbZ+qL2u8k2wtCWGTp 3YdCfIr+k6HZxtWNVQ1Egi7Mofiq82yxK1dIRNgxayxrq7r3UonSJFfy7YhEcpRkw5pP s+lIXKL43zbsR5402wVvQ90q/01MmwnBnMOLGgtAtKaSxq8WWNtfCJDUjNVbX8dknKBr sjO+74OkbcioE/8OP1ORS0oKdzw6dw9FxybxOeXfdCE6tJZhU7ZxAeztbln9EkPYcbRG bTkf2LP0LntNX0xEnlU5NecLQxpUS1GWU399tE940judQvptUKW+d4lwnpHiqPfLGreb IF4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=FI/r/KPM3NamuEvu+F9mW+RliiWbhgVxKmNTvx6BQcc=; b=nDFSRQekty2oLcA8fQjMHZBJlFcz0uZjRN3JyddbsMQuqZC+jXXdTkKVP8gkz/J414 A5kfGPwOW1Cgcub7KBl1L6uyqDtiiAN7bCuobpE3FTXA7Mv9CrlpJM6WZcP/CxSELw4P 0rGqJO3KPA6BXNLTj+8LuMqOCwwuTogS7GlF02XhInc2IcidnmMRhOe+VnWFaTTd/bBg 9ffKhhubLzm1qbN9WhucozVH+aYDJrHGDxUDRAe4XkLwksVg346c3eHTsrgkTe38hjSQ 1uOrGDp7CFGG4z0gpPsMmrYKxBwUir6uKbuAGJu8NRQPMSSK9qs/H+hI9WQpQJXmUS5F x65Q== X-Gm-Message-State: AOAM531iseNk1FvTVBeeKdil3PsNt7cngGa0A4L/F2tEg2nAx8kGAm9G l8MJmC27qulkPk5FYRafozWpQpxdiEAdbA== X-Google-Smtp-Source: ABdhPJw0LwMD3EbR1FBKH852hmnoFvx+VhSkX3kEnC3/GndsGW0vzotWC3zGi6/oUfpLjWlwj3q9YQ== X-Received: by 2002:a63:1a66:: with SMTP id a38mr3737132pgm.253.1597469360358; Fri, 14 Aug 2020 22:29:20 -0700 (PDT) Received: from [192.168.1.11] ([71.212.141.89]) by smtp.gmail.com with ESMTPSA id v78sm11468635pfc.121.2020.08.14.22.29.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 14 Aug 2020 22:29:19 -0700 (PDT) Subject: Re: [RFC v3 26/71] target/riscv: rvv-1.0: update vext_max_elems() for load/store insns To: Frank Chang References: <20200806104709.13235-1-frank.chang@sifive.com> <20200806104709.13235-27-frank.chang@sifive.com> <90f01984-54a4-2a56-c52f-d1f4332b39d4@linaro.org> <5706a1ca-1dd9-22cd-08ce-c70780111bfc@linaro.org> From: Richard Henderson Message-ID: Date: Fri, 14 Aug 2020 22:29:17 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::42d; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x42d.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "open list:RISC-V" , Sagar Karandikar , Bastian Koppelmann , "qemu-devel@nongnu.org Developers" , Alistair Francis , Palmer Dabbelt Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 8/14/20 7:52 PM, Frank Chang wrote: >     probe_pages(env, base + stride * i, nf * esz, ra, access_type); > and >     target_ulong addr = base + stride * i + k * esz; > > If we pass ctzl(sizeof(type)) in GEN_VEXT_LD_STRIDE(), > I would still have to do: (1 << esz) to get the correct element size in the > above calculations. > Would it eliminate the performance gain we have in vext_max_elems() instead? Well, no, it will improve performance, because you'll write addr = base + stride * i + (k << esz) I.e. strength-reduce the multiply to a shift. r~