Received: by 2002:ac0:a5b6:0:0:0:0:0 with SMTP id m51-v6csp89849imm; Tue, 5 Jun 2018 15:39:06 -0700 (PDT) X-Google-Smtp-Source: ADUXVKLfmzdTtBCotDoFH7GkwHHuTDVv/ZMv6WuDIO+r+wMphWwfkdDo0yZ3XQq2OZhz4dvUXFFY X-Received: by 2002:a17:902:6903:: with SMTP id j3-v6mr474393plk.313.1528238346686; Tue, 05 Jun 2018 15:39:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1528238346; cv=none; d=google.com; s=arc-20160816; b=nMKupRExIPbgDnHSLuNupeiJyFDP6faQx6ZXnOvqBZspUDaG80rSq9NQQbIzGuLutb +4UHQVPaarrvGHNPDDPOpxvmFwZUnNpTNt3fUEraPguZCE5Gf+PfI01EaCjst4CknWA0 qNPamTUzo3E0D6ZL9jTPaXFk/A7XESLzrzV6/aHVT1+IR7hWxfALeTdU5xXnKtd1pevm 2piN2zq4NLt780PiWwI4bIGE2BfzmRqMiCp/CPryrOzcE0DqsyeEELtbzKQb/WDTUE7T 3XzD/qjHzOrJc6Jt1qqtfRxt6dUiiKM/FBGFyWYj1opDYrJCzWmICvgYc4NqksuU0uM3 eNLg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-transfer-encoding:content-disposition:mime-version :references:message-id:subject:cc:to:from:date :arc-authentication-results; bh=5IrkG2C5AosrDf/Gvtk9k/p3ddT1YJiPriiT223h/38=; b=Qvpy6GmtIm6q5pHbnoePNtRoRIiiyy92O3uYV2ZDItSsPG3O8xYr5GrOyxY0hR11R7 EfuSjmNLkcbmTBVDt7jQHPl43Y74se4bEE7CEVPfbhO29+qIS+N27R0HF6REajXsCjwY h9+WhzhR6rd8g2woPnOrQd3pFYDqHgLOO2LZt5Lm1EVML9GH9bupBlfq55SpDRGdF8JW mpm+ai7m6MeQcMwZTR30fRxaRWEs7A88YUatZFwyamUltO2pmw62y4Uf3P4/tfn287D8 UWh9YUuPZwKw7Vd1eztlbzJZz5XKxXmDtOlb0gDSY8qCy73KrP88p82TXG1kAzRlpM12 4T1w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f89-v6si15069020plf.528.2018.06.05.15.38.52; Tue, 05 Jun 2018 15:39:06 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752659AbeFEWiW (ORCPT + 99 others); Tue, 5 Jun 2018 18:38:22 -0400 Received: from ipmail03.adl2.internode.on.net ([150.101.137.141]:47008 "EHLO ipmail03.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752380AbeFEWiV (ORCPT ); Tue, 5 Jun 2018 18:38:21 -0400 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail03.adl2.internode.on.net with ESMTP; 06 Jun 2018 08:08:15 +0930 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1fQKaj-00034S-F8; Wed, 06 Jun 2018 08:38:13 +1000 Date: Wed, 6 Jun 2018 08:38:13 +1000 From: Dave Chinner To: kernel test robot Cc: Dave Chinner , "Darrick J. Wong" , Christoph Hellwig , Carlos Maiolino , LKML , linux-xfs@vger.kernel.org, lkp@01.org Subject: Re: [lkp-robot] [xfs] b027d4c97b: fio.latency_2ms% +7.1% regression Message-ID: <20180605223813.GI10363@dastard> References: <20180605071657.GP16472@yexl-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180605071657.GP16472@yexl-desktop> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 05, 2018 at 03:16:57PM +0800, kernel test robot wrote: > > Greeting, > > FYI, we noticed a +7.1%% regression of fio.latency_2ms% due to commit: > > > commit: b027d4c97b9675c2ad75dec94be4e46dceb3ec74 ("xfs: don't retry xfs_buf_find on XBF_TRYLOCK failure") > https://git.kernel.org/cgit/fs/xfs/xfs-linux.git xfs-4.18-merge .... > 8925a3dc4771004b b027d4c97b9675c2ad75dec94b > ---------------- -------------------------- > %stddev %change %stddev > \ | \ > 46.56 ? 3% +7.1 53.61 fio.latency_2ms% > 8.19 +0.2 8.40 fio.latency_100ms% > 0.74 ? 3% -0.1 0.68 ? 6% fio.latency_250ms% > 25.20 ? 6% -7.3 17.86 ? 6% fio.latency_4ms% > 0.46 ? 9% +0.2 0.69 ? 13% fio.latency_750us% This is not a regression. The number of IOs in the 4ms IO latency bin has reduced by 7%, and inumber in the 2ms IO latency bin has increased by 7%. IOWs, there's a measurable improvement in IO latency as a result of those patches, not a regression. Cheers, Dave. -- Dave Chinner david@fromorbit.com