From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-x32d.google.com (mail-ot1-x32d.google.com [IPv6:2607:f8b0:4864:20::32d]) by sourceware.org (Postfix) with ESMTPS id 804543858C60 for ; Thu, 10 Feb 2022 13:22:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 804543858C60 Received: by mail-ot1-x32d.google.com with SMTP id l12-20020a0568302b0c00b005a4856ff4ceso3730660otv.13 for ; Thu, 10 Feb 2022 05:22:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=ZtSEYy/KJGdoTs7myhzB4GcJMGBav1BNgw13Tmxv5cs=; b=jflRsqF8jRrMZjIdhzUdxeUJbHjwoW9Bq8njIOY5PFoCYuFVsASkVsvFSty99NuY+e 5L/FC/GdIylWxSprSVkal1Pg4vgte3jqBdM4x+kTeLSyhNIYCDydpGQLfzicMT23V7fk HawLTMEUqdzectTfn4HI9nqln8iyiIkjxOn4FZveYFycaPpe4KFbuta4U6qOs2rtKvFk pw8OJghrRb62vlJBFU54qxB2865G7nJO6k7foN1NJlYjyLZwiSM8GfsaUX3tmeS+6M7j FPVPd54R/RjIclVY8aCDfIIz31lMLDZZDBkUdB9eN2KjcS3euA7gMh4g+lziTSWH6Uxa yavQ== X-Gm-Message-State: AOAM531jcqfvjzj1b/d6f3waAy0wBB2yPbHPtVcZ8DN7OpJxhfq8jj4S DjVGS6qhYNmpRj9cEYsS4BarHQ== X-Google-Smtp-Source: ABdhPJzJBF1WncmoA0CoxrRGgYaQ+xwDupcSKxMoUGAWMYiJI0mkylO4L8Uf8oIEz7zIJo7fyTRNVA== X-Received: by 2002:a05:6830:1314:: with SMTP id p20mr2767134otq.367.1644499330910; Thu, 10 Feb 2022 05:22:10 -0800 (PST) Received: from ?IPV6:2804:431:c7ca:733:a925:765e:3799:3d34? ([2804:431:c7ca:733:a925:765e:3799:3d34]) by smtp.gmail.com with ESMTPSA id z4sm575699oad.21.2022.02.10.05.22.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Feb 2022 05:22:10 -0800 (PST) Message-ID: <1f75bda3-9e89-6860-a042-ef0406b072c1@linaro.org> Date: Thu, 10 Feb 2022 10:22:08 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.0 Subject: Re: [PATCH v2] x86-64: Optimize bzero Content-Language: en-US To: Wilco Dijkstra , Noah Goldstein Cc: "H.J. Lu" , GNU C Library References: <20220208224319.40271-1-hjl.tools@gmail.com> From: Adhemerval Zanella In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org 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: , X-List-Received-Date: Thu, 10 Feb 2022 13:22:13 -0000 On 10/02/2022 10:17, Wilco Dijkstra wrote: > Hi, > >> We need to keep the symbols as-is afaiu, since callers might still target >> old POSIX where the symbol is defined as supported.  We might add either >> compiler or linker warning stating the symbols is deprecated, but imho it >> would just be better if we stop trying to microoptimize it and just use >> the generic interface (which call memset). > > Compilers have been doing that forever - if you use bzero GCC and LLVM > emit a call to memset. No new calls are emitted to these functions, so there > is no point in having target-specific optimization at all. > > However we could disallow use of these functions at all in future GLIBCs. Unfortunately we can not stop providing such symbols unless we start to stop being compatible to legacy POSIX. And I think we already do not use these internally. Also we can start to remove to other bstring functions as well, bcmp and bcopy.