From owner-svn-src-head@freebsd.org Sat Dec 9 23:35:01 2017 Return-Path: Delivered-To: svn-src-head@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 7265EE9BC20 for ; Sat, 9 Dec 2017 23:35:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x22f.google.com (mail-io0-x22f.google.com [IPv6:2607:f8b0:4001:c06::22f]) (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 32FB67A1DD for ; Sat, 9 Dec 2017 23:35:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x22f.google.com with SMTP id t196so6016240iof.0 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=bhROk3yyn7KfKagvcYrgwVgwu67LIVr32sMrWLOzKGUtztkma0GhlIig+1bW2MCfod TALZObvxs1lnnuidxaI/jaLRcXKP4i2Mu9cbmYiMJXMycZ6XS9mV6NMiCLpI0dmib5zw uaiMM3cO1pdxEMAjtSedVgoxpbjW07eIG+gGjzOjIEUmp/WGs+GVAFaIe+MAxoRWNoiJ EhTLM1o627pJ41ZBfdp8IUh8gFbCbv03C31HCzUZH+gcZclsFJt82RnSzpSGfdYlmglK LG4S9NGB7KAqWIYA/DMylOOYiOuZvQGvqKRnW9SNITwUpJcNW5QRwlSGX0lcF1Cac0AX HzpA== X-Gm-Message-State: AJaThX4KxVyxhPGmQ8f+L2q58CcDDkT7Ma1tO9jLNOacIv4q5w0rs7d6 YpcKTUvYkOyYe4iwZBCs8Qv8ZRZcsyLOaXNZtjjcaA== 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-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current 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.