From owner-freebsd-arm@freebsd.org Fri Mar 2 16:19:36 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 D18BBF31423 for ; Fri, 2 Mar 2018 16:19:35 +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 6760A69666 for ; Fri, 2 Mar 2018 16:19:34 +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 3ztDyl3ljBzWCYx for ; Fri, 2 Mar 2018 11:19:27 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mgm51.com; s=mgm51-02; t=1520007567; bh=WqHM3um5dIfrhIix8V5YZtM63OdrKEP9aMvUHJ/oDPc=; h=Subject:Cc:From:Message-ID:Date; b=YLU7lg0TPzUfyI48+aMXEbnd2lymfX7DEtVVI2a+q/RwU+RmrsukX8VDet01OAFBi hpjDi77YLxlD1+rTCiMkqCu+UJeV0btohAOzFDrqECZcvlmoCNikk/4IrQb3UfeZwA V1KzeoQ51mw7ZB0FihwOSKfnarA1ZbcMi8CTQJ18eDAIFUuFG2xKd9+do1lbNV/ul8 gswuIqnygwf4Ea2hkj+WZB4CsAH/9UZQj1FkXsYVNm4o7spf3dqkGqOFaxDHI2EX4D uyiPralvEehtAZK0Xjh4q66KJ/SZQ5dUhkFHsJ86oaHqwpc2JJR90dZlVeTJiAs4+Q EQiBALKvkBCHg== Received: from [IPv6:fdcf:b715:2f4d:1:7935:c9cc:21c2:33cc] (unknown [IPv6:fdcf:b715:2f4d:1:7935:c9cc:21c2:33cc]) by sentry.24cl.com (Postfix) with ESMTP id 3ztDyk43LJzkB4D for ; Fri, 2 Mar 2018 11:19:26 -0500 (EST) Subject: Re: Is maximum swap usage tunable? Cc: freebsd-arm@freebsd.org References: <20180228170311.GA26187@www.zefox.net> <20180228185517.GB26187@www.zefox.net> <8f422161-885e-aa91-eacd-018540222d65@mgm51.com> <20180228214301.GA29481@www.zefox.net> From: Mike Message-ID: Date: Fri, 2 Mar 2018 11:19:16 -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: <20180228214301.GA29481@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: Fri, 02 Mar 2018 16:19:36 -0000 On 2/28/2018 4:43 PM, bob prohaska wrote: > On Wed, Feb 28, 2018 at 02:37:36PM -0500, Mike wrote: >> 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... >> > FWIW, I've been using Sandisk Extreme USB 3 flash drives for > /usr /var/ and swap on the Pi3. It seems that flash write > speed is a tighter bottleneck than USB 2.0 ports on the Pi. > Attempts to use older, slower USB 2 flash drives on a Pi2 > didn't work, though the symptoms were never "out of swap". > buildworld is still running. I started it around 3PM (EST) on March 1. I'm seeing a lot of swap messages on the console. The text is: swap_pager: indefinite wait buffer: bufobj: 0, blkno: [varies], size: [varies]