From owner-freebsd-current@FreeBSD.ORG Sat Mar 2 23:14:40 2013 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 71D18B19 for ; Sat, 2 Mar 2013 23:14:40 +0000 (UTC) (envelope-from deeptech71@gmail.com) Received: from mail-ee0-f46.google.com (mail-ee0-f46.google.com [74.125.83.46]) by mx1.freebsd.org (Postfix) with ESMTP id EFB5989D for ; Sat, 2 Mar 2013 23:14:39 +0000 (UTC) Received: by mail-ee0-f46.google.com with SMTP id e49so3214157eek.33 for ; Sat, 02 Mar 2013 15:14:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:message-id:date:from:user-agent:mime-version:to:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=MY28nyEEpbA82BklOGe0VHBVW9P92CDPf/UJakErwwA=; b=Vp/XluH2kc87hBL/+n9ZulkqJzWdRzxNArlIcIlp89iJ2uqPuRfzkBLpAtD6RW8KE3 lGnS93hOpaKqse4MDBsaL/0zXT97Y1OQV4GxsThAsXyGHaERID9OhPAoZA3nkpVxU/OV EltgrB9Hk8Th/Dj82lHZKApzArQWYI+QJrmJ5krZ7BXKb6cnRAmlAuXkDIo2BZDFQgu+ IP2Po4xLsBrK7GGB0Nv+4hEiwZPT+c3V95o2+CY61PojMTXqYc4nOOt+L4FmPXcoE84t 5fsfo/uuj8S+5IPm9b4DofeOZU2crIPw9yLiLzmqyLbautiBGRjoknkN7Uwi5tfi9siW aK7Q== X-Received: by 10.14.193.134 with SMTP id k6mr42523371een.37.1362265642198; Sat, 02 Mar 2013 15:07:22 -0800 (PST) Received: from [192.168.1.80] (1F2E5890.dsl.pool.telekom.hu. [31.46.88.144]) by mx.google.com with ESMTPS id m46sm24285284eeo.16.2013.03.02.15.07.20 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 02 Mar 2013 15:07:21 -0800 (PST) Message-ID: <51328622.10409@gmail.com> Date: Sun, 03 Mar 2013 00:07:14 +0100 From: deeptech71 User-Agent: Mozilla/5.0 (X11; FreeBSD i386; rv:18.0) Gecko/20100101 SeaMonkey/2.15 MIME-Version: 1.0 To: freebsd-current@freebsd.org Subject: Re: access to hard drives is "blocked" by writes to a flash drive References: <51323712.5000406@gmail.com> <42B72A5B-A363-426B-9F6C-7F8B3B7E7543@FreeBSD.org> In-Reply-To: <42B72A5B-A363-426B-9F6C-7F8B3B7E7543@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 02 Mar 2013 23:14:40 -0000 On 03/02/2013 21:46, Edward Tomasz Napierała wrote: > Wiadomość napisana przez deeptech71 w dniu 2 mar 2013, o godz. 18:29: >> When one of my flash drives is being heavily written to; typically by ``svn update'' on /usr/src, located on the flash drive; the following can be said about filesystem behavior: >> >> - ``svn update'' seems to be able to quickly update a bunch of files, but is then unable to continue for a period of time. This behavior is cyclical, and cycles several times, depending on the amount of updating work to be done for a particular run of ``svn update''. >> - Access to any filesystem, whether on the said flash drive or not, seems to be hindered a lot, typically during the said "unable to continue" time. Reading of a file on a hard drive was once delayed for more than 10 seconds. Seemingly as a consequence, the starting of top(1) is also typically delayed. > > When that happens, could you do "ps axl" and see the WCHAN column > for the affected processes? Is it "wdrain"? What do you mean by "the affected processes"? The MWCHAN of an ``svn update'' contained long "wdrain" periods (but included "getblk", "drainvp", etc.). ``[bufdaemon]'' sometimes seemed to somewhat follow the "wdrain" state of ``svn update''. I've also found out that the inability for top(1) or ps(1) to start immediately has something to do with X -- in the virtual terminals, there was never a delay.