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: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 45F691F45F for ; Thu, 9 May 2019 19:58:14 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:cc:cc:subject:in-reply-to:references :date:message-id:mime-version:content-type; q=dns; s=default; b= Vf8TXgt/LRmsYJqP/BxXzVgWKeJpCFJNKBGUm4TrIqh61jcyC7fa8wnrStZwlCPl 5bh9v62lPKTBU06fNYhiJvTI3nWDqLpoR2Zr/ccenG2gugjYHEeOAeolCtAcj8NR r2L3EVnnmOU8fZVC56Zv3VJ0YeIi0R6fRTTJDsMrmaM= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:cc:cc:subject:in-reply-to:references :date:message-id:mime-version:content-type; s=default; bh=T5d7Cq 8bn7Q/L1CRlVdYv4ZIhmI=; b=hZebouBfr/cEzeZIbyWqFjOdaxhWK5t2mdz5An k0gZuukRHj8c45i8+z64jkLIaRvsKJF/VYqGo9qCDO17yiy1d1zAalOHHlfSr5Tg KHGUG2UGt9XX8U2NBLwoKyqIhZ7RYeHemwbtd+Xiqn8AZbGNIb8HZxoHaHoA7tQI uGh9c= Received: (qmail 11100 invoked by alias); 9 May 2019 19:58:12 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 11092 invoked by uid 89); 9 May 2019 19:58:11 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: gecko.birch.relay.mailchannels.net X-Sender-Id: dreamhost|x-authsender|tuliom@ascii.art.br X-Sender-Id: dreamhost|x-authsender|tuliom@ascii.art.br X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|tuliom@ascii.art.br X-MailChannels-Auth-Id: dreamhost X-Sponge-Callous: 4d4070d51dbd4ea0_1557431887352_2116422896 X-MC-Loop-Signature: 1557431887352:4048522860 X-MC-Ingress-Time: 1557431887352 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=ascii.art.br; h=from:to:cc :cc:subject:in-reply-to:references:date:message-id:mime-version :content-type; s=ascii.art.br; bh=T5d7Cq8bn7Q/L1CRlVdYv4ZIhmI=; b= qFUau+jOvMxU5yBE7QDw66nWxSuJFvw8NAEb6z7Z4nthmDwysjQ9x7ZkOhcM1YO+ cfdgFT22KwS69uvE+Cw4BlYSKY3PjVNgVwy9WplCFjPKbclOJZaok8S2ICn220UD Kf1YF/6GBZpBzRq3d8wwxvCZgkzzVZz/RLccryGSqGw= X-DH-BACKEND: pdx1-sub0-mail-a52 From: Tulio Magno Quites Machado Filho To: Shawn Landden , Joseph Myers Cc: libc-alpha@sourceware.org Cc: Subject: Re: [PATCH] powerpc: add libmvec implementations of log and logf In-Reply-To: References: <20190505203438.28140-1-shawn@git.icu> <20190506203210.8536-1-shawn@git.icu> User-Agent: Notmuch/0.27 (http://notmuchmail.org) Emacs/25.3.1 (x86_64-redhat-linux-gnu) Date: Thu, 09 May 2019 16:58:02 -0300 Message-ID: <878svfqu2d.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-VR-OUT-STATUS: OK X-VR-OUT-SCORE: -90 X-VR-OUT-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduuddrkeeigdekfecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucggtfgfnhhsuhgsshgtrhhisggvpdfftffgtefojffquffvnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenfghrlhcuvffnffculddutddmnecujfgurhephffvufgjfhgffffkgggtsehttdertddtredtnecuhfhrohhmpefvuhhlihhoucforghgnhhoucfsuhhithgvshcuofgrtghhrgguohcuhfhilhhhohcuoehtuhhlihhomhesrghstghiihdrrghrthdrsghrqeenucfkphepfedvrddutdegrddukedrvddtvdenucfrrghrrghmpehmohguvgepshhmthhppdhhvghloheprghstghiihdrrghrthdrsghrpdhinhgvthepfedvrddutdegrddukedrvddtvddprhgvthhurhhnqdhprghthhepvfhulhhiohcuofgrghhnohcusfhuihhtvghsucforggthhgrughoucfhihhlhhhouceothhulhhiohhmsegrshgtihhirdgrrhhtrdgsrheqpdhmrghilhhfrhhomhepthhulhhiohhmsegrshgtihhirdgrrhhtrdgsrhdpnhhrtghpthhtoheplhhisggtqdgrlhhphhgrsehsohhurhgtvgifrghrvgdrohhrghenucevlhhushhtvghrufhiiigvpedt Shawn Landden writes: > When I first looked at Bert's patch I saw all the scalar code for the > special path and thought it wasn't a real vector implementation. > Otherwise I wouldn't have tried to compete with him. > > HOWEVER, once I fixed the bugs in my benchmark programs, there is no > performance advantage of doing either log or logf with vector > operation, at least on this power 9 VPS---either mine or Bert's > patches. I think this is because they require too many table lookups > for the constants, and Power ISA 3.0 lacks both a gather instruction, > and a permutexvar instruction, both of which could be used to > vectorize these table lookups. (shufflevector can't do it) Base on this information and considering that you haven't a FSF copyright assignment, which means I can't look at your patch, I plan to merge Bert's patches. Thank you! -- Tulio Magno