From owner-freebsd-stable@freebsd.org Wed Nov 4 14:31:36 2015 Return-Path: Delivered-To: freebsd-stable@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 097B2A26F5B for ; Wed, 4 Nov 2015 14:31:36 +0000 (UTC) (envelope-from tevans.uk@googlemail.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 CB9431E7E for ; Wed, 4 Nov 2015 14:31:35 +0000 (UTC) (envelope-from tevans.uk@googlemail.com) Received: by iody8 with SMTP id y8so54988663iod.1 for ; Wed, 04 Nov 2015 06:31:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=V4pcFbtgEwb56INSLzwSlMWAsEmZItQB3RUOruHnhyg=; b=tC5xtIxgdI598HicfxE4idAh5RCoX4l4B3meeYpNxEQF3KWZ757rUkgscLv2hVy2Vk RPdH6TxwgclAA6aJhxAbfsfFefouAygvS9AWNSVvZ6s7zx754QCPuzRhLNGizrfBwhJP +MU052spAlyT51yMzb2SUMr2/FwIvD4FbmlOCtfH87ymf/pEJGlnl3UY1AIIiuzZL07m nC2CQG8psQpEPg71Oq40gEyQYsU7GxAqVDjvI7J4KqxJ9XitnLLVYBi7lxG9VrstPUnt HuSpPb/yiMOez4Coald8mk74660N5v1F/TTu5jf64866twihfXcBnNDvsw4OATiREcB6 uk6Q== MIME-Version: 1.0 X-Received: by 10.107.10.204 with SMTP id 73mr3879087iok.22.1446647495264; Wed, 04 Nov 2015 06:31:35 -0800 (PST) Received: by 10.107.46.8 with HTTP; Wed, 4 Nov 2015 06:31:35 -0800 (PST) In-Reply-To: <20151104025748.F10372@sola.nimnet.asn.au> References: <20151027050508.GA7612@icarus.home.lan> <20151104025748.F10372@sola.nimnet.asn.au> Date: Wed, 4 Nov 2015 14:31:35 +0000 Message-ID: Subject: Re: stable/10: high load average when box is idle From: Tom Evans To: Ian Smith Cc: FreeBSD Stable Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Nov 2015 14:31:36 -0000 On Tue, Nov 3, 2015 at 5:47 PM, Ian Smith wrote: > Like yourself, I think this is far from 'cosmetic' as is oft suggested, > especially in some fairly ill-informed forum posts but also various list > posts. I've been watching load averages since OS/2 through FreeBSD 2.2 > till present and some Linux systems, and have never before seen anything > like this, especially on virtually entirely idle systems. While the LAs > reported during (say) make -j4 buildworld appear more same, who knows? > > I'm not suggesting that I think there's any sort of performance hit from > this; so far I don't, but 'cosmetic' suggests that it doesn't matter .. > Have you read mav's explanation on the PR? It certainly seems a valid explanation of why it is probably a cosmetic issue - that is, we could wake up more to get a truly perfect load average, but why bother? ISTM, the problem reports are of the form "My server is idle and it is reporting a non-idle load average below 1", and not "My server is supposedly idle, but is doing actual work causing the load average to be higher than it should be". Is there any evidence that we have the latter and not the former? Cheers Tom