From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa1-x2b.google.com (mail-oa1-x2b.google.com [IPv6:2001:4860:4864:20::2b]) by sourceware.org (Postfix) with ESMTPS id 25BA33857BA4 for ; Fri, 11 Aug 2023 15:48:29 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 25BA33857BA4 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-oa1-x2b.google.com with SMTP id 586e51a60fabf-1c4af84667bso343613fac.1 for ; Fri, 11 Aug 2023 08:48:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1691768908; x=1692373708; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=QYbMJXCk5h8zG16HxDMwIFTcILoTOKX9gAGDajfM7qs=; b=fhbW1+D6pRtBIVOxNzDOvHvJIkQDXc+stFZfB/xpGi/Zec6IHMWptDWsePpCsuRgv2 /RPN+Euq/M5hUslOjni1CMPJ7lcHBVejo7gwg03fQ+Ro9XOuDY4BGlI+r4iQEwMPr4y7 ang/tQlSYabjIUCfUrPN6tFRrkpb1TFelWm7a24RmAGE6kfReB0opCzNMrs9xT7Qfd1S Qb9lHx7WbC/2TIgd//ZWQqorMycwmBJ/D2MALgWPa5gtVIHQRBPUIR+whe+pl6qAupDb NsV6qDntV2IP3ShMuv+EdN47LqIj4wovOr3XJn8FwSU61aZNKnFXDJxvjpJdHaa8UVUp DDPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691768908; x=1692373708; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QYbMJXCk5h8zG16HxDMwIFTcILoTOKX9gAGDajfM7qs=; b=Mm9czn9Pyr+RQTRWztW2eac1ta2ODFtaIkO3KD+i3gxHKcThb2GEIe4KS435SYgDFe z4pYSfV94gnRf1IsMzlr2TJ5dRAkZY/EcNBE+/j2AE55qpbCYqDxQFfHbxpgOXBcGOw8 E6v9EPatSjV7lUDTBdL1pvLCtV8iagmgNqBF/Jtm618Wn2s5G2DSUs7gwewbXdiDIPSH ijywDcNwn7L3GZ4pzqedD2qqfzQMRUGC7LPSE9KMKtjIBk41A4Jxqf6F3ztq2tdsDdFS i24VZU1UBwLxcEm3Jbuz0oVKrxs4VWkGILx1REUVDr+ICnesZ8hIlqq2/bZumkOzoC9t dOZw== X-Gm-Message-State: AOJu0Yy2zdgXal1ao7Kideraqh2mY9ZtzdxtAlYTlgR333/jglcYeUYv BQcCEDGRgyVhth1f2bp9m/g= X-Google-Smtp-Source: AGHT+IEnYcfvjWvX4vcD4hF55k5kBLxpaoNDH9w5f8p9f0k+/kAHQ6AsEJPC/1ZvPQHCzr3bkqYzrQ== X-Received: by 2002:a05:6870:6114:b0:1bc:1ad8:2b7b with SMTP id s20-20020a056870611400b001bc1ad82b7bmr2272071oae.58.1691768908302; Fri, 11 Aug 2023 08:48:28 -0700 (PDT) Received: from [172.31.0.109] ([136.36.130.248]) by smtp.gmail.com with ESMTPSA id 19-20020a17090a031300b002677739860fsm3687524pje.34.2023.08.11.08.48.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Aug 2023 08:48:27 -0700 (PDT) Message-ID: <4f971a10-44ae-773d-5b50-e54efd95678d@gmail.com> Date: Fri, 11 Aug 2023 09:48:26 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH] RISC-V: Revert the convert from vmv.s.x to vmv.v.i Content-Language: en-US To: Lehua Ding , gcc-patches Cc: "juzhe.zhong" , "kito.cheng" , "rdapp.gcc" , palmer References: <20230811090121.1789446-1-lehua.ding@rivai.ai> <2A2BF09C15AEBD43+tencent_C5EBE2190BE4F3FA9E5D56CE5EBBF88FA607@qq.com> From: Jeff Law In-Reply-To: <2A2BF09C15AEBD43+tencent_C5EBE2190BE4F3FA9E5D56CE5EBBF88FA607@qq.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 8/11/23 09:43, Lehua Ding wrote: > > I can't speak for other uarches, but as a guiding principle for Ventana > > we're assuming vsetvl instructions are common and as a result need to be > > very cheap in hardware.   It's likely a good tradeoff for us. > > > I could see other uarches making different design choices though.  So at > > a high level, do we want this to be driven by cost modeling in some way? > > > Not a review yet.  Wanted to get that feedback to you now since the rest > > of my day is going to be fairly busy. > > Thanks for the feedback. We'll think about it some more. > Just out of curiosity, will the combination of vsetvli + vmv.v.x perform > better than li + vmv.s.x on Ventana's CPU? It's context dependent, but in general vsetvli+vmv would generally be better than li + vmv. jeff