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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 83750C433FE for ; Fri, 7 Oct 2022 15:27:25 +0000 (UTC) Received: from localhost ([::1]:50840 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ogpG0-0000mI-Bx for qemu-devel@archiver.kernel.org; Fri, 07 Oct 2022 11:27:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54038) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ogney-0000ev-D5 for qemu-devel@nongnu.org; Fri, 07 Oct 2022 09:45:04 -0400 Received: from mail-wr1-x42f.google.com ([2a00:1450:4864:20::42f]:41723) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ognew-0006i1-JZ for qemu-devel@nongnu.org; Fri, 07 Oct 2022 09:45:04 -0400 Received: by mail-wr1-x42f.google.com with SMTP id bu30so7362057wrb.8 for ; Fri, 07 Oct 2022 06:45:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:from:to:cc:subject:date :message-id:reply-to; bh=7qYRJtrJLjzmBVoNiWl95ssE0Z+o9iqE2SKt6mBGqBo=; b=G0Suqt5WlWTqC7j28JPiMxWkDGsOf1QCSeGHTtAdZwJoMtEaxBMvuo5qk/ofrqskpp ZRlSZIJj6j4Go/4aI9W1oCtbvWILXNVRs31AMQe5BBV2/SSogjkgmvXOPnMrHzHlhYlN x/Lnlns+PXBrdHCRIGIPndeuSpa0l70cjFPDwx9DJWNCBBzIFntHhfZ7I8MSUKpGSlQx iSVv/etzinToc8rR6G0PNEpqoZiExP8hwOBWL+fjgUYBUBoSjgmF/WQAuXTM7VDs2o6m j3NeNVB5BOTEGXh/joiJNnXUkCL2kEhEg9qMpLzhHXG0crKTtV0j3kM1TO4B5Khc1//+ eXeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=7qYRJtrJLjzmBVoNiWl95ssE0Z+o9iqE2SKt6mBGqBo=; b=RS3UFnh/yAlMurIL/ugIFOHZ0+Satm33Zi5e4IE8/b+zFjCQlf8N+/1di6DitSiwZb N1cWrpS5PNlwDuD9AS5ZuEHGMx7kAYA7HESuV6/R6lceUgiSz0UxyHL6gN6H7QBuqqS2 K2U4nS/y9ad0Wo+yyDnknSZPoVlB6TFejbSr1Zb45gAut3t4FK480J78Y4kxd2S2gVQK IlpVu4RcaJber8PsyqaoWTf93lw0FPzjrrQ981b2kcM+/f1AuXgNR/7c/nCUWIekRUrH z54E9bLKXcSDRgP/q6AqykM+aOGP7VzNf7Tp8SAlS0VEsX2P5o42a789hX/Z66U5RhFb 6nAQ== X-Gm-Message-State: ACrzQf2eSRBedrzWWOwMe03OXH63nGEJOHXpmCEEcABjbsoi4sfT2E5J 0cXf1LNVQfSHSIWz3+aWEONGTSMFQeMa9Q== X-Google-Smtp-Source: AMsMyM6joDYlXVKXX2gOEVduKmhie1aZcNjSlWqyoQTOYcOlmpKqy68TSMPZMx44gOdyKzOjTEdKBA== X-Received: by 2002:a5d:58d3:0:b0:22c:e8e4:1461 with SMTP id o19-20020a5d58d3000000b0022ce8e41461mr3295413wrf.227.1665150301152; Fri, 07 Oct 2022 06:45:01 -0700 (PDT) Received: from zen.linaroharston ([185.81.254.11]) by smtp.gmail.com with ESMTPSA id r11-20020a05600c2c4b00b003bf3fe1d0c4sm2301631wmg.22.2022.10.07.06.45.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Oct 2022 06:45:00 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id D02F61FFB7; Fri, 7 Oct 2022 14:44:59 +0100 (BST) References: <20221005143719.65241-1-victor.colombo@eldorado.org.br> User-agent: mu4e 1.9.0; emacs 28.2.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Richard Henderson Cc: =?utf-8?Q?V=C3=ADctor?= Colombo , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, clg@kaod.org, danielhb413@gmail.com, david@gibson.dropbear.id.au, groug@kaod.org, aurelien@aurel32.net, peter.maydell@linaro.org, balaton@eik.bme.hu, matheus.ferst@eldorado.org.br, lucas.araujo@eldorado.org.br, leandro.lupori@eldorado.org.br, lucas.coutinho@eldorado.org.br Subject: Re: [RFC PATCH 0/4] Idea for using hardfloat in PPC Date: Fri, 07 Oct 2022 14:42:55 +0100 In-reply-to: Message-ID: <87a667iw84.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::42f; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x42f.google.com 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Richard Henderson writes: > On 10/5/22 07:37, V=C3=ADctor Colombo wrote: >> However, the impact in performance was not the expected. In x86_64 I >> had a small 3% improvement, while in a Power9 machine there was a small >> performance loss, as can be seem below (100 executions). >> | | min [s] | max [s] | avg [s] | >> | before | 122.309 | 123.459 | 122.747 | >> | after | 123.906 | 125.016 | 124.373 | > > I hope this is because you didn't handle the most common cases: add, sub,= mul, div. > > The logic seems plausible, as far as it goes, and would work for the > FR bit as well which afair isn't handled at all at the moment. I'll > review properly in a little while. I wonder if this is something that could be generalised and pushed up into the fpu stuff itself. We could after all cache the op and decomposed parameters here in a generic way. The trick would be working out how to do that without slowing down the current common case. Is ppc unique in not persisting the inexact flag from previous operations? > > > r~ --=20 Alex Benn=C3=A9e