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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26D1FC43334 for ; Fri, 24 Aug 2018 18:50:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2B722151C for ; Fri, 24 Aug 2018 18:50:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="gQ5pcsHZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2B722151C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727192AbeHXW0k (ORCPT ); Fri, 24 Aug 2018 18:26:40 -0400 Received: from mail-io0-f194.google.com ([209.85.223.194]:41624 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbeHXW0j (ORCPT ); Fri, 24 Aug 2018 18:26:39 -0400 Received: by mail-io0-f194.google.com with SMTP id q4-v6so7933413iob.8 for ; Fri, 24 Aug 2018 11:50:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=7falQ6vJZgobqKYv+GpbnoF18oJtcIry5jMkzy8aWT0=; b=gQ5pcsHZ6Zoy77qt7qsu4VPz+77OHYtqYq69MPjKFy1gy6ViPJyT9algzqsR2bYeYV YqzFPc/b6NmfDgXz/Fy4ZU7tQSKsl8VLwgCh2ScEQds3kkTZvz8a+pgHAHCf0e9S5rTk yaJ7MxhTr7b9LIwvo3v8nPsgUxUpzGFfGogY4f8XP7YoxUaERfzT8Xz2i/glwArITz+J D9L5J1a7yAhwh5r0iPEu8bo8HRG4Kh45B2Jh5IAl5th6s0ymHBUKs+jDQvPyzRXzQCVb 6y2ghWPTN0Ir3md1t4hSXiVrP6mGANE8KFWv9xMp/ZQMLzT9dWCRACE61XDHsOBspnFl ErrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=7falQ6vJZgobqKYv+GpbnoF18oJtcIry5jMkzy8aWT0=; b=Csov3LUQ59kEb1La/t3uIJELJXZ240eq8MbPlFehuwSbXeVZnTF3tq4g3Vf9MfC4yP FU/B4hD2oZqL8N94+P8sKI6URpLEvFmcpiHOA3cQSSol7GdVejKu/2ZiziqeY9toX9j6 0oJTZCnmIKzT4GiAOTCSsECVd6uKmT1FuhvUUI1E/1KZlBs6WiOAttKu/zQ2aGHwzfsF yU7/Zb0XdaEfwuR8aifxkXAOKdWY0BcZfFSNsa+Bkar3G9GgozqS6q8X1FJ6cDN8PaM/ 05v4vr/hV/dlzlZIv5ZbrQaYrNJKnGTaHl5Nx62SxvyDJSPzX+E+hBLxl+87ji/57uE1 lLVg== X-Gm-Message-State: APzg51AZ74h2IrQXPmzjarTfk09FyaJ86gB+loc7hrZMNj7MFsSN2qsi xWyCJXmmUPxUFj5PUKyQPxoLuA== X-Google-Smtp-Source: ANB0VdZkRbGL3PFLQkb5xjWyYnu8xYAHvHWeDZNaKwJueVnn2ZVRd3htS15rBrNEREkongVyPRBy6g== X-Received: by 2002:a6b:9108:: with SMTP id t8-v6mr2269177iod.260.1535136648194; Fri, 24 Aug 2018 11:50:48 -0700 (PDT) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id n1-v6sm2615008ioh.31.2018.08.24.11.50.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Aug 2018 11:50:46 -0700 (PDT) Subject: Re: [PATCH] blk-wbt: get back the missed wakeup from __wbt_done To: Anchal Agarwal Cc: fllinden@amazon.com, Jianchao Wang , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , anchalag@amazon.com References: <1535029718-17259-1-git-send-email-jianchao.w.wang@oracle.com> <20180823210144.GB5624@kaos-source-ops-60001.pdx1.amazon.com> <3eaa20ce-0599-c405-d979-87d91ea331d2@kernel.dk> <20180824181223.GA9049@kaos-source-ops-60001.pdx1.amazon.com> From: Jens Axboe Message-ID: <677c8648-63fd-601c-b906-40a8502f9782@kernel.dk> Date: Fri, 24 Aug 2018 12:50:44 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20180824181223.GA9049@kaos-source-ops-60001.pdx1.amazon.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/24/18 12:12 PM, Anchal Agarwal wrote: > That's totally fair. As compared to before the patch it was way too high > and my test case wasn't even running due to the thunderign herd issues and > queue re-ordering. Anyways as I also mentioned before 10 times > contention is not too bad since its not really affecting much the number of > files read in my applciation. Also, you are right waking up N tasks seems > plausible. OK, I'm going to take that as a positive response. I'm going to propose the last patch as the final addition in this round, since it does fix a gap in the previous. And I do think that we need to wake as many tasks as can make progress, otherwise we're deliberately running the device at a lower load than we should. > My application is somewhat similar to database workload. It does uses fsync > internally also. So what it does is it creates files of random sizes with > random contents. It stores the hash of those files in memory. During the > test it reads those files back from storage and checks their hashes. How many tasks are running for your test? -- Jens Axboe