From owner-freebsd-current@freebsd.org Sun Feb 10 20:55:22 2019 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C7AAA14DB701 for ; Sun, 10 Feb 2019 20:55:22 +0000 (UTC) (envelope-from zeising+freebsd@daemonic.se) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 1EF1D6A5C0 for ; Sun, 10 Feb 2019 20:55:22 +0000 (UTC) (envelope-from zeising+freebsd@daemonic.se) Received: by mailman.ysv.freebsd.org (Postfix) id D3ABF14DB6FC; Sun, 10 Feb 2019 20:55:21 +0000 (UTC) Delivered-To: current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B10D714DB6FA for ; Sun, 10 Feb 2019 20:55:21 +0000 (UTC) (envelope-from zeising+freebsd@daemonic.se) Received: from mail.daemonic.se (mail.daemonic.se [176.58.89.161]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 49BB86A5BF for ; Sun, 10 Feb 2019 20:55:20 +0000 (UTC) (envelope-from zeising+freebsd@daemonic.se) Received: from cid.daemonic.se (localhost [IPv6:::1]) by mail.daemonic.se (Postfix) with ESMTP id 43yLln51YRzDjTP; Sun, 10 Feb 2019 20:55:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=daemonic.se; h= content-transfer-encoding:content-language:content-type :content-type:in-reply-to:mime-version:user-agent:date:date :message-id:from:from:references:subject:subject:received :received; s=20151023; t=1549832117; bh=zdyN/Q4LS9/Hm0ZMcsHiSJFh ywYFppA3OVbp2nwInWQ=; b=uh9TKCj5BkUpSmdr7pw5CGhaAqswXSbx5imYaTlQ AWvyzoEUH8NVJAJnDXlG22U9Jnu3xpZc0IyLkrjgGV6VaJI3EiUIRm3hfIPewZ3w eB51ljvhQtZPrVYrhACVVtsDIgMx9Fr2YXqrBna4rozZ+KOHPnnaP3oycmzQp3Wl kTs= X-Virus-Scanned: amavisd-new at daemonic.se Received: from mail.daemonic.se ([IPv6:::1]) (using TLS with cipher ECDHE-RSA-AES128-GCM-SHA256) by cid.daemonic.se (mailscanner.daemonic.se [IPv6:::1]) (amavisd-new, port 10587) with ESMTPS id hAJr6-PW7ZBK; Sun, 10 Feb 2019 20:55:17 +0000 (UTC) Received: from [IPv6:2001:470:dca9:2:f577:da68:d7aa:723f] (unknown [IPv6:2001:470:dca9:2:f577:da68:d7aa:723f]) by mail.daemonic.se (Postfix) with ESMTPSA id 43yLlm5SpdzDjCL; Sun, 10 Feb 2019 20:55:16 +0000 (UTC) Subject: Re: "Oddness" in head since around r343678 or so To: Alexander Leidinger , "Rodney W. Grimes" , current@freebsd.org References: <201902071536.x17FaPtI051105@pdx.rh.CN85.dnsmgr.net> <168cc6f6518.27fa.fa4b1493b064008fe79f0f905b8e5741@Leidinger.net> From: Niclas Zeising Message-ID: <51739ca5-7662-6040-1da3-01f08e85bbb8@daemonic.se> Date: Sun, 10 Feb 2019 21:55:16 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 49BB86A5BF X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-6.98 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[]; NEURAL_HAM_SHORT(-0.98)[-0.983,0]; TAGGED_FROM(0.00)[freebsd] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 10 Feb 2019 20:55:23 -0000 On 2019-02-10 16:35, Niclas Zeising wrote: > On 2019-02-08 10:27, Alexander Leidinger wrote: >> Hi, >> >> I recently noticed some generic slowness myself. I experienced this=20 >> during replacing disks in a raidz by bigger ones. Long story short,=20 >> check top -s if you have vnlru running for a long period at high=20 >> CPU... If yes increase kern.maxvnodes (I increased to 10 times). Note,= =20 >> we should improve the admin page in the FAQ, the vnlru entry could=20 >> need a little bit more hints and explanations. >> >> If you encounter the same issue we have probably introduced a change=20 >> somewhere with an unintended side effect. >> >> Bye, >> Alexander. >> >=20 > Hi! > I'm seeing this as well, on 13-CURRENT.=C2=A0 I updated a computer from= the=20 > last January snapshot (30 or 31 of January, I can't remember) and it=20 > seems disk IO is very slow.=C2=A0 I remember having a svn checkout taki= ng a=20 > very long time, with the SVN process pegged at 100% according to top.=C2= =A0 I=20 > can't see the vnlru process running though, but I haven't looked=20 > closely, and I haven't tried the maxvnodes workaround.=C2=A0 Something = has=20 > changed though. > This is systems using ZFS, both mirror and single disk.=C2=A0 Gstat sho= ws=20 > disks are mostly idle. >=20 > I know this is a lousy bug report, but this, and the feeling that thing= s=20 > are slower than usual, is what I have for now. > Regards Hi! I did some more digging. In short, disabling options COVERAGE and=20 options KCOV made my test case much faster. My test: boot system create a new zfs dataset (zroot/home/test in my case) time a checkout of https://svn.freebsd.org/base/head, putting the files=20 in the new zfs dataset. This is in no way scientific, since I only ran the test once on each=20 kernel, and using something on the network means I'm susceptible to=20 varying network speeds and so on, but. In this specific scenario, using a kernel without those options, it's=20 about 3 times faster than with, at least on the computer where I ran the=20 tests. I noticed in the commit log that the coverage and kcov options has been=20 disabled again, albeit for a different reason. Perhaps they should=20 remain off, unless the extra runtime overhead can be disabled in=20 runtime, similar to witness. Regards --=20 Niclas