From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-4.4 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI,NICE_REPLY_A, RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 8D7571F8C6 for ; Tue, 13 Jul 2021 19:03:34 +0000 (UTC) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id A7FE2396E861 for ; Tue, 13 Jul 2021 19:03:33 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A7FE2396E861 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1626203013; bh=OX5Jqt/O5hwKfjfSW1WtZL6rh7I+cNNfyJaopwVs4og=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=OKKC0k4vKgMI+LD3w8LII1JODZeXwG0u39jM3Aryohu4IXBcAlhn/eqPBuMEmDW6F /NdxV2wr3MAyiuOw1JpYusWY+t8WDLI6o9zB11KvIVloF9ubkc6870kWKKEKsjhChT FQRogyAX4//IxrtaGqsbUrBtFx3M1tGq50AZ9Uv8= Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by sourceware.org (Postfix) with ESMTPS id 1D80D38515F6 for ; Tue, 13 Jul 2021 19:03:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 1D80D38515F6 Received: by mail-pj1-x1035.google.com with SMTP id b5-20020a17090a9905b029016fc06f6c5bso2696482pjp.5 for ; Tue, 13 Jul 2021 12:03:14 -0700 (PDT) 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=OX5Jqt/O5hwKfjfSW1WtZL6rh7I+cNNfyJaopwVs4og=; b=gQmD9iAbLXriS6HsQlE9tSh0RsdofPABbIxEA2lbVn1AFacRtkCPwpgHjk7/Pmh1TM Tm+9NfQzFRqGOsfQjKC7F8xNeX1m4Yy7rpP6iVIliEOZHO712xM8NZluudhAOqQLHcFb iQ0VdtJph9b7UOvCa+gefdbS7VqG/iKtzCGfYFnDnkiB7qIxrp0rxIaMZOjKY6MePjfJ Rzm3v6S7X9eOGtSBSbDBr8CSb3N7/vf40muzreQtXuOpwpw+4zxhi2jEoSCuE4wmIDr7 I1g9A3zf95ovvoWPcrkIYDjlzawJXI7RJbBgEBlijmdpc+eUyO6/OyRgIctexgVAHWeh +Llg== X-Gm-Message-State: AOAM530gLf7kd6Zh5sUjI6T1bNYQIidXDQV05a+dOR5+QbzFCkhY6uVR HbyceZgPY76ZJ95TQRNhcQ1R9RxvQvMLSA== X-Google-Smtp-Source: ABdhPJy1vP87anipm4MKWqEHqTqEGhBor7+1Dby/PwDbiTP6cOJpb4XzYtN5u/AkOVIfS2RjQ9BfnQ== X-Received: by 2002:a17:90a:5305:: with SMTP id x5mr724775pjh.135.1626202992954; Tue, 13 Jul 2021 12:03:12 -0700 (PDT) Received: from [192.168.1.108] ([177.194.59.218]) by smtp.gmail.com with ESMTPSA id i8sm3568152pjh.36.2021.07.13.12.03.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Jul 2021 12:03:12 -0700 (PDT) Subject: Re: [PATCH 1/3] powerpc64: Replace some PPC_FEATURE_HAS_VSX with PPC_FEATURE_ARCH_2_06 To: Tulio Magno Quites Machado Filho , Anton Blanchard References: <20210706105107.1866836-1-anton@ozlabs.org> <87k0m0l9rh.fsf@linux.ibm.com> Message-ID: <4241d750-5999-4a68-3c7f-faa1b3927577@linaro.org> Date: Tue, 13 Jul 2021 16:03:10 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <87k0m0l9rh.fsf@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Adhemerval Zanella via Libc-alpha Reply-To: Adhemerval Zanella Cc: libc-alpha@sourceware.org Errors-To: libc-alpha-bounces+e=80x24.org@sourceware.org Sender: "Libc-alpha" On 08/07/2021 19:29, Tulio Magno Quites Machado Filho via Libc-alpha wrote: > Anton Blanchard via Libc-alpha writes: > >> We use PPC_FEATURE_HAS_VSX to select a number of POWER7 optimised >> functions. These functions don't use any VSX instructions, so >> PPC_FEATURE_ARCH_2_06 seems like a better fit. > > I don't think we can replace PPC_FEATURE_HAS_VSX with PPC_FEATURE_ARCH_2_06 > because it would cause issues similar to the ones fixed in patch 3/3, i.e. > this function would run on a processor that implements the Power ISA 2.06 > but does not implement Altivec. > > So, if testing for PPC_FEATURE_ARCH_2_06 is important, I think it has to test > for: > > (hwcap & PPC_FEATURE_ARCH_2_06 && hwcap & PPC_FEATURE_HAS_ALTIVEC) > > However, VSX was introduced by Power ISA 2.06. So, PPC_FEATURE_HAS_VSX > implies PPC_FEATURE_ARCH_2_06. PPC_FEATURE_HAS_VSX also implies > PPC_FEATURE_HAS_ALTIVEC. > The change would only make a difference if a processor implements both Power > ISA 2.06 and Altivec, but does not implement VSX. > > Am I missing anything? My understanding is the selection change done for this patch is to enable routines that do *not* use vectorized instructions (either VSX or altivec) on a CPU that does have isa 2.06 (to use cmpb for instance). That's why I suggested that we should in fact rename them and also maybe move to a different folder than 'power7' to something more meaningful (for instance __memchr_isa206 or something). The selection change above you suggested is not strictly required, it would be for memcpy/memmove (if I recall correctly they only use altivec). > > Another important point is to keep the tests in the IFUNC resolvers in sync > with sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c > Otherwise, glibc tests and benchtests may not execute correctly. >