From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oo1-xc2b.google.com (mail-oo1-xc2b.google.com [IPv6:2607:f8b0:4864:20::c2b]) by sourceware.org (Postfix) with ESMTPS id 4A2D93858D1E for ; Tue, 7 May 2024 21:30:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4A2D93858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 4A2D93858D1E Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::c2b ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1715117434; cv=none; b=K3jZhAP851ClKb6DTGc399gsloGJxddfChGjLTiIBXdkGfT2ETsLI0jXAbzozQkGmPNCt/wE0ZWCiOxaMv8XqLATYGskJsCAcDNeq2kN/Kf31Rh/y0LNiUcXunqlWiDF/jDsWHEqdQMerzJeerd2tBmfukv4DrWc9YBitGyvv5c= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1715117434; c=relaxed/simple; bh=CKiGMS9MQxDzJSwBoWi2qjYhSg6lDixSOuGP7/LL2Tc=; h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From; b=maRg6a73PmnXQn4ehT37vHz8+TVTObyDdQbhy7hwZcsjM8SUENMhDQj2tt6AUHlvSxdhE8jDhdzrY61EBOfUt1dph1SSA3YPXp5dOAe0yNrfwPHs2S/fHUUF6faDotINtCIcJGL7+n8DI/4f3VLwIU3UC1JnsKYsmMdzQ3mAu1g= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-oo1-xc2b.google.com with SMTP id 006d021491bc7-5aa3f0fcd46so2141923eaf.1 for ; Tue, 07 May 2024 14:30:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1715117432; x=1715722232; darn=gcc.gnu.org; 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=TLi2/+kpD8GWIsL25FU47LHed5SQt2Q1/Dxnzmtn6mE=; b=C2jqdamuHR5Yx0o+4B7NnQ+tMVo+4qQFDdxPce6CEI+5Dy9vPEvZQAMHe6Yu1HXvar U1irakhH8FWu5rWIROjjWhcDUeXDI5gX+Moegn9cJhXVLGoL3/whn0eOfC0vdTvLwTzs Njx4An3Sw5W3SE1ns6XWxIqkiMqJyHmDNn1guLzplIJMHCHRJZiVN0YvX+be8idkFRys 96RO8YRyhKkWBAZRT8YHEnhWyAFu8NeUVsi1ODlTdg9bXtlQbXiUdYscIaabbictzhwj GBGDPZvqI9pPalqMbHKPYA+jFCFtef1888SVmHFiD50K9voyKYaswAwdqAZTCoDnzQXo /2cQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715117432; x=1715722232; 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=TLi2/+kpD8GWIsL25FU47LHed5SQt2Q1/Dxnzmtn6mE=; b=IsICy/4eyuy2AlKyIbO7qX8W6AtPZ+yVu+SVgE/mTsIaMAQ81ROVefO6JKliX3LigL 4qWNWCFP5xmayTjYqUCZ4YsF1yQ1W3vd8JqVF6USzUIBaaxuxu2rrB30/iGKbRXBfFfF TVDGVoCfjlbNj/AW+FYrPGX/gZFBjjITXkuoBBzLU6qKSFm9oUz3agfAWn5ePYgaqwIV WPSh0yN1nUKJ68WMEk9HvjRQj9Ya+FM21GBysigbV6rnPm24W1Jw+bbEviHB0uT40zTt YQdnk4ObFYw37pQMjywz847OtlbA9XTzIBiFfosm7Tuz1zLEeuxBJ0z4Pft3ZGFnN45S Dt6Q== X-Gm-Message-State: AOJu0YzDBzEM/gM/zu9Akd1xd0XAQqvOp4+QEEHL3i8IDHl6DHVAFxkb JD4DKRpEon6+dfF0U1HA8AQonl3jbjufIAPnoncEDqMIRkqO4FGC X-Google-Smtp-Source: AGHT+IFfc+J5XLB8cLlSkSOSc5jbcmq49wRT5IAXCs+E27dNz3dMnqhRC2Z+2KZ83RH6W8Addp7L9A== X-Received: by 2002:a4a:58c2:0:b0:5ac:da5a:3198 with SMTP id 006d021491bc7-5b24d649117mr746058eaf.6.1715117432511; Tue, 07 May 2024 14:30:32 -0700 (PDT) Received: from [172.31.0.109] ([136.36.72.243]) by smtp.gmail.com with ESMTPSA id bh15-20020a056820088f00b005b1e10646a5sm2143961oob.39.2024.05.07.14.30.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 May 2024 14:30:32 -0700 (PDT) Message-ID: Date: Tue, 7 May 2024 15:30:31 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [committed] [RISC-V] Allow uarchs to set TARGET_OVERLAP_OP_BY_PIECES_P Content-Language: en-US To: Palmer Dabbelt , Jeff Law Cc: gcc-patches@gcc.gnu.org References: From: Jeff Law In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,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 5/7/24 3:24 PM, Palmer Dabbelt wrote: >> @@ -529,6 +536,7 @@ static const struct riscv_tune_param generic_ooo_tune_info = { >> 4, /* fmv_cost */ >> false, /* slow_unaligned_access */ >> false, /* use_divmod_expansion */ >> + false, /* overlap_op_by_pieces */ > > IMO we should turn this on for the generic OOO tuning -- the benchmarks > say it's not faster for the T-Head OOO cores, but we were all so > surprised to find that I don't think we even fully trust the benchmarks. > I'd assume OOO cores are faster with the overlapping stores, so we > should just lean into it and let vendors say something if that's the > wrong assumption. Several factors likely come into play (branch prediction, OOO properties, write combining, etc etc). But sure, I don't think that'd be terribly controversial. I can go ahead and make that change now given its triviality. Jeff