From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60392C433F5 for ; Fri, 27 May 2022 10:26:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350032AbiE0KZ7 (ORCPT ); Fri, 27 May 2022 06:25:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234079AbiE0KZ7 (ORCPT ); Fri, 27 May 2022 06:25:59 -0400 Received: from mail-ej1-x62d.google.com (mail-ej1-x62d.google.com [IPv6:2a00:1450:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0056F61295 for ; Fri, 27 May 2022 03:25:57 -0700 (PDT) Received: by mail-ej1-x62d.google.com with SMTP id gi33so7917522ejc.3 for ; Fri, 27 May 2022 03:25:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ZCzKx/HY0X/xtRmnKEGtxVXaMKlqjGwxMl14qIIXnx0=; b=HGaef/di1cJqwqCjrGZlw5lsDEk0XeaHfs9PNRk6qcwIZGxVYsi/RX6YtP9yEkT3Ll ZP7LHbdHDCtBnOfEEQDh7/C75/hdoSZvMzMSAmuS6O7or1xoK4Fp21VkRbLY+bH7l322 laN4DN3fBmkOyKEQGakH3utTQb3lHZo2e2yOWWJtj2ePtWeQEV2grrcRHSCAYDiXn1Da hi43NvTSRahqKl8mhQ7E3lMcgMYWQZa96ij9UZClVl6nk/MQWkFvmv4ZZGVLBMrLs9qE PCDOdgbfz3lsFHZMdFIHc7gLM297ja/+JRyUMWGZWVlPJwr2HiV7d0vRMZYhKX5ZAySz dP9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=ZCzKx/HY0X/xtRmnKEGtxVXaMKlqjGwxMl14qIIXnx0=; b=3DgC2qh1LBYl6VETPH0qOxcoAy+2fQQQZObw2kFKvtp/LqOsnuXHWVsO984CeIAx6z FB0qVpIHHyavSjF0lsqZqPy85dZyPtwkZYTwK0tRWQRSVnRy4HIMMD6i1GOaE45drkCw vWs1ipY+9MQk9Cot7EisCyMP2AzjOrSXohuZJ6D6lh46HiL1pPrDyOmGTQFprfMFNkvC iUkk5FC5Vz5g4GjH5rNh1xPKHQn8oKdqdWYw54HotDOOhZTeb7dciNOAvlcncuVseybp Cgrmb1TQYWEvDD4g+jfeGcy3bY3FELkkcQPFtVcXEjs2Mn7LB3l+JLukgpdHtk5JZ+eC V0dQ== X-Gm-Message-State: AOAM531mf1/YjgNIL4Aajb7zhb42Q8Ly/YMWgi2yxf959eMP43yHBsu+ zkcM+LjjyEay+LO9qSgKtlo= X-Google-Smtp-Source: ABdhPJzUl8J0WQ0lwwpZ0SuauX1plH1rjAiVmByjmQMriEHpD+2zSywoiDU+jLyq5Yl5gsZuueqQBg== X-Received: by 2002:a17:907:97d1:b0:6f8:5aa9:6f16 with SMTP id js17-20020a17090797d100b006f85aa96f16mr37672181ejc.587.1653647156374; Fri, 27 May 2022 03:25:56 -0700 (PDT) Received: from gmail.com (563BA16F.dsl.pool.telekom.hu. [86.59.161.111]) by smtp.gmail.com with ESMTPSA id dv5-20020a170906b80500b006f3ef214dd1sm1308619ejb.55.2022.05.27.03.25.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 May 2022 03:25:55 -0700 (PDT) Sender: Ingo Molnar Date: Fri, 27 May 2022 12:25:53 +0200 From: Ingo Molnar To: "Jason A. Donenfeld" , Samuel Neves Cc: Jens Axboe , Matthew Wilcox , Al Viro , Christoph Hellwig , linux-fsdevel@vger.kernel.org, x86@kernel.org Subject: Re: [RFC] what to do with IOCB_DSYNC? Message-ID: References: <0343869c-c6d1-5e7c-3bcb-f8d6999a2e04@kernel.dk> <6594c360-0c7c-412f-29c9-377ddda16937@kernel.dk> <2ae13aa9-f180-0c71-55db-922c0f18dc1b@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org * Ingo Molnar wrote: > > * Jason A. Donenfeld wrote: > > > On Mon, May 23, 2022 at 10:03:45AM -0600, Jens Axboe wrote: > > > clear_user() > > > 32 ~96MB/sec > > > 64 195MB/sec > > > 128 386MB/sec > > > 1k 2.7GB/sec > > > 4k 7.8GB/sec > > > 16k 14.8GB/sec > > > > > > copy_from_zero_page() > > > 32 ~96MB/sec > > > 64 193MB/sec > > > 128 383MB/sec > > > 1k 2.9GB/sec > > > 4k 9.8GB/sec > > > 16k 21.8GB/sec > > > > Just FYI, on x86, Samuel Neves proposed some nice clear_user() > > performance improvements that were forgotten about: > > > > https://lore.kernel.org/lkml/20210523180423.108087-1-sneves@dei.uc.pt/ > > https://lore.kernel.org/lkml/Yk9yBcj78mpXOOLL@zx2c4.com/ > > > > Hoping somebody picks this up at some point... > > Those ~2x speedup numbers are indeed looking very nice: > > | After this patch, on a Skylake CPU, these are the > | before/after figures: > | > | $ dd if=/dev/zero of=/dev/null bs=1024k status=progress > | 94402248704 bytes (94 GB, 88 GiB) copied, 6 s, 15.7 GB/s > | > | $ dd if=/dev/zero of=/dev/null bs=1024k status=progress > | 446476320768 bytes (446 GB, 416 GiB) copied, 15 s, 29.8 GB/s > > Patch fell through the cracks & it doesn't apply anymore: > > checking file arch/x86/lib/usercopy_64.c > Hunk #2 FAILED at 17. > 1 out of 2 hunks FAILED > > Would be nice to re-send it. Turns out Boris just sent a competing optimization to clear_user() 3 days ago: https://lore.kernel.org/r/YozQZMyQ0NDdD8cH@zn.tnic Thanks, Ingo