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=-0.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,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 36B69C433E1 for ; Sat, 15 Aug 2020 22:00:02 +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 01C29206B6 for ; Sat, 15 Aug 2020 22:00:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="eJecjkNW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01C29206B6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45568 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k74DZ-0003x5-3K for qemu-devel@archiver.kernel.org; Sat, 15 Aug 2020 18:00:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38290) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k74Cz-0003VZ-0Z for qemu-devel@nongnu.org; Sat, 15 Aug 2020 17:59:25 -0400 Received: from mail-ot1-x342.google.com ([2607:f8b0:4864:20::342]:41332) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1k74Cx-0001B0-0O for qemu-devel@nongnu.org; Sat, 15 Aug 2020 17:59:24 -0400 Received: by mail-ot1-x342.google.com with SMTP id a65so10493289otc.8 for ; Sat, 15 Aug 2020 14:59:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=bCin6TmgTSZWrgtfO6/BybfYU3ZQRUite8vCDBRZoh0=; b=eJecjkNW4Wcw/UhB9GuLXR4D3b7PrzJHOLR7tuXHWmnpq/yMJQ86cFq4eZG1lOEcpa yz7wjE6DkXg0FWB2lKdPsvjfw5OLnvKdZXEjLsurIiszZAExWw0ycSIdB4Nh5BOzwQrG HFBMlFwfikjJ2g1ngZWi4N6FNMoZ3uZr0f+SFknHUSbFrt+tAYCT8Vv8O10A09pG4Jbi +BgVPZgLYr2Fwczx80tLk8omfH7jRG0jeDlxzuUlp64gVejo1VWo/HGhdW12r5H5KujF 4lIFBWywg4p/cJ3bfAZBSt61S9iB/qoGobhsFCZE+u7Fd+vZhImZfIuAxt1NHfyr5dmK SD5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=bCin6TmgTSZWrgtfO6/BybfYU3ZQRUite8vCDBRZoh0=; b=mC1tIzRhAQW1xW4/UG3DMMXArYcbP+Sie0RFCqwlsgfG/8P5gKzjd3UAZa3ceCOo3r /Do3KQtJ8mczrFayi3iSxTOrF7EL6+kHLPR3CumhZ68AyG9yhIDPZhjTYXV98dqvGpHw 6b7dT4IgB4CRIoRuj82MKae+2Za8zaBSEVXS3zcchHagNM/BiSU+Zva72ANUB6Gz2wh4 qP6JDQPVK0QckuSLHXGBXSWUf2aEAg/jnKCzt13B6oipzLycgcChYmS5E5+50wzC8UZx EjVQ4EYZNi0VKaOsY8gdaHaSYfxGKaW21fRqp7BrfqpSY40J1YLRcIfcp2aefTkIEp3d oXcA== X-Gm-Message-State: AOAM533li4AqdNU1nEvkhx6HXtpFFJc6W70mWw7mATabWfVFqkI3N70N hZj26dR/Frtbl4kpg52N+8gaR98+3O3klVftPCVfDg== X-Google-Smtp-Source: ABdhPJwPblhMNoruxqo35v5uX6B3U+67Y5PP4TdGgzqC+ww6k1Wmg3iRQ4SmixoygJCeKis4Dana91XL9Ngohyc8IX4= X-Received: by 2002:a9d:3443:: with SMTP id v61mr6693131otb.139.1597528761661; Sat, 15 Aug 2020 14:59:21 -0700 (PDT) MIME-Version: 1.0 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> In-Reply-To: From: Frank Chang Date: Sun, 16 Aug 2020 05:59:12 +0800 Message-ID: Subject: Re: [RFC v3 26/71] target/riscv: rvv-1.0: update vext_max_elems() for load/store insns To: Richard Henderson Content-Type: multipart/alternative; boundary="0000000000005b929805acf1a63e" Received-SPF: pass client-ip=2607:f8b0:4864:20::342; envelope-from=frank.chang@sifive.com; helo=mail-ot1-x342.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, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=unavailable 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" --0000000000005b929805acf1a63e Content-Type: text/plain; charset="UTF-8" On Sat, Aug 15, 2020 at 1:29 PM Richard Henderson < richard.henderson@linaro.org> wrote: > 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. > > This works like a charm. Thanks for the advice. Frank Chang > r~ > > --0000000000005b929805acf1a63e Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Sat, Aug 15, 2020 at 1:29 PM Richard H= enderson <richard.hender= son@linaro.org> wrote:
On 8/14/20 7:52 PM, Frank Chang wr= ote:
> =C2=A0 =C2=A0 probe_pages(env, base + stride * i, nf * esz, ra, access= _type);
> and
> =C2=A0 =C2=A0 target_ulong addr =3D base + stride * i + k * esz;
>
> If we pass ctzl(sizeof(type)) in=C2=A0GEN_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=C2=A0vext_max_elems= () instead?

Well, no, it will improve performance, because you'll write

=C2=A0 addr =3D base + stride * i + (k << esz)

I.e. strength-reduce the multiply to a shift.


=
This works like a charm.
Thanks for the advice.
<= div>
Frank Chang=C2=A0

=C2=A0
<= blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-l= eft:1px solid rgb(204,204,204);padding-left:1ex"> r~

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