From owner-svn-src-head@FreeBSD.ORG Wed Aug 28 10:44:30 2013 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 289F5B1C; Wed, 28 Aug 2013 10:44:30 +0000 (UTC) (envelope-from davide.italiano@gmail.com) Received: from mail-vb0-x231.google.com (mail-vb0-x231.google.com [IPv6:2607:f8b0:400c:c02::231]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id A4B022CE8; Wed, 28 Aug 2013 10:44:29 +0000 (UTC) Received: by mail-vb0-f49.google.com with SMTP id w16so3866388vbb.36 for ; Wed, 28 Aug 2013 03:44:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=QHuc1ifI0o6IPBiEAv+rzjJx65W+ej7cUCXO8HIaFRA=; b=i7v0k1AOqhoCsMw27VmfNPTqcYSmPMS5H2x++Vu+FHd3xwkdRIkb4tRrHz9tjnrVYN Re0o9Y+womUQwTEWM9RAeVanU31Ba68yktsSKALipJqmaNJJCHuNklrtMnXLcluI2Mtl dENaU+6yPTO7poIjRCWNH4SHfiKrRJGCdLFmjHvNRgDH6Qw5/Jzh/0uJ8IG8UrdcDzYM uZZgJdH76l3D4K0mlWU8XKQ7yKX3YjGwQuCoTyHx/bUv5d9tUAj4JI0cumPIaqtDfJp9 v3Qb+I28MVIjhmUYaHMz5VX/pCT85hLjIt9WapK+kOzLNV+NNGKss6vEd56CrGpPtco7 UO0g== MIME-Version: 1.0 X-Received: by 10.221.44.136 with SMTP id ug8mr24958313vcb.13.1377686668813; Wed, 28 Aug 2013 03:44:28 -0700 (PDT) Sender: davide.italiano@gmail.com Received: by 10.220.65.132 with HTTP; Wed, 28 Aug 2013 03:44:28 -0700 (PDT) In-Reply-To: References: <201308281006.r7SA6KSq010737@svn.freebsd.org> Date: Wed, 28 Aug 2013 12:44:28 +0200 X-Google-Sender-Auth: JXocqAvDe-csFpL9mlQsDbLlD2g Message-ID: Subject: Re: svn commit: r254986 - head/sys/ufs/ufs From: Davide Italiano To: Ivan Voras Content-Type: text/plain; charset=ISO-8859-1 Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 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: Wed, 28 Aug 2013 10:44:30 -0000 On Wed, Aug 28, 2013 at 12:31 PM, Ivan Voras wrote: > On 28 August 2013 12:25, Davide Italiano wrote: > >> do you have any evidence that this change impacts positively (or >> negatively) performances for some workloads? If yes, can you share? > > Yes, observation of my own servers. Without this, dirhash is basically > useless since in certain situations everything gets evicted after 5 > seconds and it never grows to its full potential. > Oh, well. Your servers doesn't necessary reflect FreeBSD general user so you can just maintain this change local. I've always thought FreeBSD policy was that of leaving reasonable defaults for the general case and giving people possibility to tune them according to their needs. Also 'in certain situations' makes relatively little sense to me unless you provide a testcase that mimics such situations or explain to people how to reproduce it. >> Also, why did you choose the '60' value (rather than something else)? > > Personal experience. > Do you realize that this is a driven by commit change, right? And there's no technical motivatiion about this or experimental data that confirms you've chossen the right value? >> I don't see any 'Reviewed by:' line in your commit message neither I >> remember a public discussion on -current or -arch or -fs about this. >> OTOH I think such changes deserve a wider discussion. > > See discussion in @stable. I see from the archives that you didn't get any feedback by anyone working in the VM layer or by some UFS maintainer. I don't even comment about discussing -CURRENT changes in stable@. Thanks, -- Davide "There are no solved problems; there are only problems that are more or less solved" -- Henri Poincare