From owner-svn-src-all@freebsd.org Sat Dec 9 23:35:01 2017 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6D668E9BC1F for ; Sat, 9 Dec 2017 23:35:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x22d.google.com (mail-io0-x22d.google.com [IPv6:2607:f8b0:4001:c06::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 257977A1DA for ; Sat, 9 Dec 2017 23:35:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x22d.google.com with SMTP id o2so2592405ioe.8 for ; Sat, 09 Dec 2017 15:35:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=kJS7tHPfyocmeZiqTj1XURUuKP5xsB0ohr83mpX0YNs=; b=WJf3UaLJ6l79qAngsbfJeRwU/6pmadg+VMiNpXBZhSs072oRMYvtov8qLTtOM4QmAb TGT2cH4EfxA7AZ6IRlXyUbvqNvJBqjpFSLR+AGGn1DZwsEnA/bN0m5C/laNVbdLm/3Lt bx44cabM8yAVs6p3RcO4yXUVlaEjiksAoOp8QKzWzpnsV1Pt28u7qsiKbuFn3VYy6DlJ NJf1YhXzhGxejD5FVs4Yc0ww1FH86giQEdNjpUyUtaRTVMSODnxSgoqMpVvzWTB84kwy dp515nTJKFNihkSmmEVBN2awvtsy3iqkYqk++m97OFSJnEOPZbPGLnptpv1pC7bJFeNf iyDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=kJS7tHPfyocmeZiqTj1XURUuKP5xsB0ohr83mpX0YNs=; b=SK6H+/uFRZJtmErg7DhZhQ1k5IQ4mGTWS3dW2AHPmoyMK0WPzigJwoupLMDUwp0jd3 6FEsTwYvD1RBS/FajvTO26nfFtW/+sdfUvcXP/DZ628zqZA+V7zDbImqjwKNjUrN1OMH i8gn9y95sZPWGeTgQjGfvVo5BOyNRBRQP33x+9p34EH6K+bESga+vT6Fjz6R/Q0wzbZN 1zURFqpMXluLehqN1+KcKFtUTlQuTUZKVkfzBz0mVjgHcJTovVtFtS1h4e6T2MI+gosa K14AEt6Xkx6Dx6UJMu8ax4WvU+Xmvim77i0foGqTa60agvjsWlCBQL4UYDx5Dv+NekYQ AnLg== X-Gm-Message-State: AJaThX7WSHRuwYhScZ06+QejglLjsywjuqhsUDCKqwIrryngMhzzKC9U 70OAwdypCZDi9llScHFwfHFhv4g8AgkJcP8LO4tlUQ== X-Google-Smtp-Source: AGs4zMYbWVzls3AeH+vdr7TL+PY/u5A9bB8D++Z9AXwxCU3pTie+qq8YiZaTccHC5/6oplJWXF+nV+P/nNNhmiXx/KQ= X-Received: by 10.107.48.197 with SMTP id w188mr49518288iow.301.1512862500345; Sat, 09 Dec 2017 15:35:00 -0800 (PST) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.79.108.204 with HTTP; Sat, 9 Dec 2017 15:34:59 -0800 (PST) X-Originating-IP: [2607:fb90:6cac:851b:54b5:2218:52a:92a0] Received: by 10.79.108.204 with HTTP; Sat, 9 Dec 2017 15:34:59 -0800 (PST) In-Reply-To: <73189.1512862030@critter.freebsd.dk> References: <201712091544.vB9FiVUI096790@repo.freebsd.org> <20171209223713.GA15275@raichu> <73189.1512862030@critter.freebsd.dk> From: Warner Losh Date: Sat, 9 Dec 2017 16:34:59 -0700 X-Google-Sender-Auth: BEtc_WXmNnjWk-COq-AX2mckvA8 Message-ID: Subject: Re: svn commit: r326731 - head/sys/ufs/ffs To: Poul-Henning Kamp Cc: Mark Johnston , Andriy Gapon , src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 Dec 2017 23:35:01 -0000 On Dec 9, 2017 4:27 PM, "Poul-Henning Kamp" wrote: -------- In message , Warner Losh writes: >I also noticed that gsched doesn't take BIO_ORDERED into account when >sorting requests. Isilon has an I/O scheduler which has this problem >too > >I think the cam iosched ignores it too. That would be strange given that BIO_ORDERED is @gibbs baby ? Nah... I wrote the iosched code... and I find the concept somewhat flawed since it is at the disk level, not the partition level, so it winds up interfering with mixed traffic. And it really only makes sense for writes, but it affects reads. And it is a poor fit to Ata semantics, and not a lot better for scsi. And for nvme it creates a bottleneck in hardware carefully designed to be free of bottlenecks... Warner Warner -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.