From owner-freebsd-fs@FreeBSD.ORG Fri Feb 25 00:37:04 2011 Return-Path: <owner-freebsd-fs@FreeBSD.ORG> Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 674EF1065673 for <freebsd-fs@freebsd.org>; Fri, 25 Feb 2011 00:37:04 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-wy0-f182.google.com (mail-wy0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id 02ACF8FC14 for <freebsd-fs@freebsd.org>; Fri, 25 Feb 2011 00:37:03 +0000 (UTC) Received: by wyb32 with SMTP id 32so1350207wyb.13 for <freebsd-fs@freebsd.org>; Thu, 24 Feb 2011 16:37:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=+TmSPS4z0Ks9mH+dEhJDdO0shorSU+7uV1a5+0CmJBk=; b=a7SfQYmmrGj0oHLaYGM2IoXT55XZPSuxr6ZuIQ3yV79b+oiEdI9DrB+DXZ2agEwXIJ cvYsA7RfqB29k39w5PwGK3v3494P7BXZfkjOg7ww/I0vy4Fm+SYROf4oyPkxET35nUZS OA364zmC/bOr31Pt9rpEQvYzKpZRaEU13Vlf4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=FUgiE2FUZBSOXw/HdwaQ0h7Onhkurpk0OPM93DqfWR0qZ4WbvfH4GsxsL7gSXS7t4C eOqBeHUK/lDYXTe9ccZPdU9zYYVXT2BmibWtUt7vLUCSEk+L9eXS56yHvcowKiHqVlJS FEUBkdkk0HrEy/0qyvWifpbywehQ5hsZKexh4= MIME-Version: 1.0 Received: by 10.216.50.193 with SMTP id z43mr1454048web.49.1298594223010; Thu, 24 Feb 2011 16:37:03 -0800 (PST) Received: by 10.216.15.74 with HTTP; Thu, 24 Feb 2011 16:37:02 -0800 (PST) Date: Thu, 24 Feb 2011 16:37:02 -0800 Message-ID: <AANLkTiko+Q2t1Qm_XnoRbnTGa42640ZriDuq_w1+bBQJ@mail.gmail.com> From: Garrett Cooper <yanegomi@gmail.com> To: freebsd-fs@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: Are ru_inblock/ru_oublock in struct rusage used in capturing all block/cluster activity? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems <freebsd-fs.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>, <mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs> List-Post: <mailto:freebsd-fs@freebsd.org> List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>, <mailto:freebsd-fs-request@freebsd.org?subject=subscribe> X-List-Received-Date: Fri, 25 Feb 2011 00:37:04 -0000 Hi FS folks, I'm trying to get a better understanding of these two statistics recorded by getrusage(2): long ru_inblock; /* block input operations */ long ru_oublock; /* block output operations */ Are the block operations limited to filesystem access on disk, or do they also apply to filesystems not backed by physical media, like memory disks, tmpfs, etc? It looks like it applies to all vnode operations in areas (the kern/vfs_*.c files), so I would assume that it applies to non-physical backed filesystem access as well, but just to be sure I thought I would ask the experts. ru_inblock and ru_oublock summed together compose the ac_io statistic used by acct(2), so I'm curious as to whether or not the utility of acct(2) on non-physical media backed filesystems was intentional. Thanks, -Garrett PS As a bonus question, why is ac_io a float primitive if it's just a sum of two longs?