From owner-freebsd-arm@freebsd.org Wed Feb 28 19:37:46 2018 Return-Path: Delivered-To: freebsd-arm@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 918B2F3FDE9 for ; Wed, 28 Feb 2018 19:37:46 +0000 (UTC) (envelope-from the.lists@mgm51.com) Received: from oneyou.mgm51.net (oneyou.mgm51.net [174.136.99.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "oneyou.mgm51.net", Issuer "RapidSSL RSA CA 2018" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2EC3D89A6C for ; Wed, 28 Feb 2018 19:37:45 +0000 (UTC) (envelope-from the.lists@mgm51.com) Received: from sentry.24cl.com (sentry.24cl.com [IPv6:2001:558:6017:94:c582:1d99:a986:7609]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "sentry.24cl.com", Issuer "Mike's Certificate Authority" (verified OK)) by oneyou.mgm51.net (Postfix) with ESMTPS id 3zs5SR6MT7zWCVy; Wed, 28 Feb 2018 14:37:43 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mgm51.com; s=mgm51-02; t=1519846664; bh=ofko/flzEMSjeM9EqyfdZ+CQIBk1FKi/6MbA/wELxzE=; h=Subject:To:Cc:From:Message-ID:Date; b=lWO2+I70/rycwrf/NxEPR6XUv0ByIlyUXdmTS6z8XDrhpYi4Ex3voje5VcXZr57WE TnX4QQVMKvrCUGwxO8ToWZnRAC1vAHBrO7bpd/3NL0MZ5rYU2FWDfHDBX6zk41unug v79GYQgWVoK4hBub9xLWpdmZEsId8k/wOHizoqYXIEsIjGrkV5gMLTFZgkM17k4pZ1 ShfVndpnDFQlB1cBIsxRE24y5i0KMEV3k3CKT6C5K0tmKK+knUDaBcEBbIGh0FIB7k RBle4dWNSR2SBZAxSTNAwWcsFAB+O0EXID3DTNC1dkuJuyQ3LCtiayrLOEGuoZ2dru YljJ5WpUm0ocw== Received: from [IPv6:fdcf:b715:2f4d:1:a968:662f:4999:7781] (unknown [IPv6:fdcf:b715:2f4d:1:a968:662f:4999:7781]) by sentry.24cl.com (Postfix) with ESMTP id 3zs5SQ6KydzkB4D; Wed, 28 Feb 2018 14:37:42 -0500 (EST) Subject: Re: Is maximum swap usage tunable? To: bob prohaska Cc: freebsd-arm@freebsd.org References: <20180228170311.GA26187@www.zefox.net> <20180228185517.GB26187@www.zefox.net> From: Mike Message-ID: <8f422161-885e-aa91-eacd-018540222d65@mgm51.com> Date: Wed, 28 Feb 2018 14:37:36 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180228185517.GB26187@www.zefox.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Feb 2018 19:37:46 -0000 On 2/28/2018 1:55 PM, bob prohaska wrote: > On Wed, Feb 28, 2018 at 12:20:56PM -0500, Mike wrote: >> On 2/28/2018 12:03 PM, bob prohaska wrote: >>> In watching system compilations on an RPi3 it looks as if the >>> system starts killing processes with "out of swap" warnings >>> well below 50% of full utilization (in this case, 2 GB). One >>> recent instance of make -j4 kernel-toolchain killed llvm-tblgen >>> with only 34% of the swap in use. >>> >>> Is the maximum swap usage limit adjustable in any way? I didn't >>> recognize anything useful in the page at >>> https://www.freebsd.org/cgi/man.cgi?query=sysctl(8)&sektion=&manpath=freebsd-release-ports >>> >>> It's possible the problem is really swap speed, rather than size, so I'd >>> like to try changing size limits if possible. The swap media claims 2-3 >>> MB/sec random write speed and observations with gstat seem to support the >>> claim, but transient stalls are hard to observe. An RPi2 with similar >>> hardware seems to have no problems. >>> >> >> >>> It's possible the problem is really swap speed >> >> I was running into swap speed / timeout issues. There were messages on >> the console to that effect. >> >> Once I put the swap space on rotating rust, that part of the compile >> problem disappeared. I use 1GB swap space. >> > > The latest kernel versions seem to have largely done away with the > "indefinite wait buffobj" warnings. They're few and far between, > the compile proceeds unless they're abundant. The fact that armv7 > has no problem, and the system is reporting "out of swap" with 34% > in use strikes me as suspicious. Kernel and userland are in sync, > so the figure of 34% swap usage is probably accurate. > > Perhaps my question is better phrased thus: How does FreeBSD-arm > determine when it's out of swap? > Thanks for the follow-up. I was planning to download and try the RPI3-20180226-r330034 image file this evening. Per your comment, I'll not use the rusty swap space, and see what happens. I'll report back, probably on the morrow... thx.