From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25739 invoked by alias); 9 Jul 2018 14:27:05 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 25407 invoked by uid 89); 9 Jul 2018 14:27:04 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=71, 7.1 X-HELO: mail-ua0-f196.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Cd1uptA0cVcf4TmhqDbSWHnamsLFjDT4t88lnuM2DQg=; b=Sf5aqUBT4FPPW53URLomeEf7vGWE63szOZXTuPuMbs+f+eFY1T2YnRSFY5wdtUg6hf 93nUMyxxe0eOwimNPS3Hhm+hPWXPdHiAzBoYkksB3xJcClmb59e1N9ziASPmFWUDmNAB ccDRGTj/FgZrBtRpaqX3LWSKrjiBJ0/DGAlWc= Return-Path: Subject: Re: [PATCH 00/10] Optimized math routines To: Szabolcs Nagy , libc-alpha@sourceware.org Cc: nd@arm.com References: <50b1b8b6-d03c-224f-31ff-8cf9d8268b6d@redhat.com> <25ede414-21e9-bc19-c624-197c3435a346@arm.com> <414348c2-6538-c9c3-9c4d-2cd922f50cdc@arm.com> From: Adhemerval Zanella Openpgp: preference=signencrypt Message-ID: <774b6ba6-d5b2-7a1f-a1ee-b7629d4981be@linaro.org> Date: Mon, 09 Jul 2018 14:27:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <414348c2-6538-c9c3-9c4d-2cd922f50cdc@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SW-Source: 2018-07/txt/msg00237.txt.bz2 On 09/07/2018 10:34, Szabolcs Nagy wrote: > On 09/07/18 14:09, Adhemerval Zanella wrote: >> On 09/07/2018 09:15, Szabolcs Nagy wrote: >>> built and tested on a power8 machine now, glibc math >>> tests pass (except for an unrelated fmal failure), >>> benchmark improvements are consistent with aarch64/x86_64, >>> but it was a shared access machine so i won't post exact >>> numbers, sincosf improved a bit too, sinf/cosf didn't >>> (apparently powerpc has its own implementation). >> >> PowerPC sinf/cosf uses the same algorithm used on x86, I presume >> it would be a gain to generic implementation as well. >> > > you mean the new implementation would be better or the > target specific one? > > new implementation has better latency on this particular > powerpc machine than the target specific code, but > throughput is worse sometimes (using the default 0 > setting for PREFER_FLOAT_COMPARISON). I did not measure, but I would expect. PowerPC uses an different implementation for generic code (s_sinf-ppc64.c) so comparing against it maybe misleading (since it use the old implementation still). I am not sure which compiler you used for evaluation, but at least Ubuntu 16.04 one (gcc 5.4) does not use POWER8 ISA as default and even with -mcpu=power8 it generates subpar code. I will try to check with a GCC 7.1 (but as for your environment, I am using a shared machine, although it I think I might get slight better results because it uses a micro-partition). For PREFER_FLOAT_COMPARISON, do we use this on glibc? I think it is only enabled on optimized-routines, isn't it?