From owner-freebsd-hackers@FreeBSD.ORG Wed Aug 28 16:12:34 2013 Return-Path: Delivered-To: freebsd-hackers@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 CB85C1EF; Wed, 28 Aug 2013 16:12:34 +0000 (UTC) (envelope-from gljennjohn@googlemail.com) Received: from mail-bk0-x236.google.com (mail-bk0-x236.google.com [IPv6:2a00:1450:4008:c01::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 0903A24EF; Wed, 28 Aug 2013 16:12:33 +0000 (UTC) Received: by mail-bk0-f54.google.com with SMTP id mz12so2303987bkb.13 for ; Wed, 28 Aug 2013 09:12:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=date:from:to:cc:subject:message-id:in-reply-to:references:reply-to :mime-version:content-type:content-transfer-encoding; bh=Q0UFBFG3OQNSfIVBxQ8BX4LdUN5McWVDaf4Dnx2WrqI=; b=c8xMzHl0G+Fn3wODqLRuLBFKLiniTwzjpks5wM9E/TIoQ/lAEHpGn2R2QzeA9mfKl3 TMKJHNZAnJ/JTtjYBAag7S65Pe7eLHVa0IpnHuMsEDKcjA7kUYXlbeRgn9B95HOZIv+B 3k5mIouz9LzVrfcf+ECPUK1G1uBMmYGUQszNrGnry9n5YUkt2CTgW9jh4QoUj4GdGnZG llh24dTP2PhSzr/nbU7GiZ0qAjDwUxWIiesCfjghB2hqAuZipWeG+mreRLQzSW1dsLNa NGYjEVj6/2MvJQP6ilbLHf0kapWSAOMTPv7H7TpmqGSUfiAiwVdQlbY/NoPJL4h6Big8 V5DA== X-Received: by 10.204.62.70 with SMTP id w6mr101436bkh.43.1377706351474; Wed, 28 Aug 2013 09:12:31 -0700 (PDT) Received: from ernst.home (p578E0A66.dip0.t-ipconnect.de. [87.142.10.102]) by mx.google.com with ESMTPSA id jt14sm6184548bkb.0.1969.12.31.16.00.00 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Wed, 28 Aug 2013 09:12:30 -0700 (PDT) Date: Wed, 28 Aug 2013 18:12:28 +0200 From: Gary Jennejohn To: Ivan Voras Subject: Re: Call fo comments - raising vfs.ufs.dirhash_reclaimage? Message-ID: <20130828181228.0d3618dd@ernst.home> In-Reply-To: References: X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.17; amd64-portbld-freebsd10.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org, freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: gljennjohn@googlemail.com List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Aug 2013 16:12:34 -0000 On Wed, 28 Aug 2013 15:56:30 +0200 Ivan Voras wrote: [jump to the chase] > Why not leave it for sysadmins to tune it themselves if they want it: > > 1) They usually don't know about it until it's too late. > > 2) Dirhash is typically miniscule compared to todays memory sizes - a > few dozen MBs even on very busy systems, and there are no typical > situations where a large number of entries are filled in at the same > time which block eviction of a large-ish amount of memory, so having > reclaimage higher will automatically help in file-system intensive > spikes without harming other uses. > So, if I understand this correctly, a normal desktop user won't notice any real change, except that buildworld might get faster, and big servers will benefit? But could this negatively impact small, embedded systems, which usually have only small memory footprints? Although I suppose one could argue that they usually don't have large numbers of files cached in memory at any given time. -- Gary Jennejohn