From owner-freebsd-hackers@FreeBSD.ORG Mon Feb 7 13:44:30 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AD78B1065673; Mon, 7 Feb 2011 13:44:30 +0000 (UTC) (envelope-from doconnor@gsoft.com.au) Received: from cain.gsoft.com.au (cain.gsoft.com.au [203.31.81.10]) by mx1.freebsd.org (Postfix) with ESMTP id 276868FC21; Mon, 7 Feb 2011 13:44:29 +0000 (UTC) Received: from ur.dons.net.au (ppp203-122-198-229.lns6.adl6.internode.on.net [203.122.198.229]) (authenticated bits=0) by cain.gsoft.com.au (8.14.4/8.14.3) with ESMTP id p17DiN1D082826 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Tue, 8 Feb 2011 00:14:24 +1030 (CST) (envelope-from doconnor@gsoft.com.au) Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: text/plain; charset=us-ascii From: "Daniel O'Connor" In-Reply-To: Date: Tue, 8 Feb 2011 00:14:23 +1030 Content-Transfer-Encoding: quoted-printable Message-Id: <88A9D148-7E3C-4ADB-90FC-B95C4D3BBD2E@gsoft.com.au> References: <53A394ED-7C2E-4E4B-A9A7-CB5F1B27DBE3@gsoft.com.au> <7108E013-77D1-47F8-892E-5027DB7D432B@gsoft.com.au> <990005CD-39BD-45F6-BD07-ACEE79DF5A03@gsoft.com.au> <772B352C-7241-4326-8B49-3FB675896609@gsoft.com.au> <71549325-5FD1-4516-B49E-098AFBEFE8B7@gsoft.com.au> To: Ivan Voras X-Mailer: Apple Mail (2.1082) X-Spam-Score: 0.163 () BAYES_00,RDNS_DYNAMIC X-Scanned-By: MIMEDefang 2.67 on 203.31.81.10 Cc: freebsd-hackers@freebsd.org Subject: Re: Scheduler question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Feb 2011 13:44:30 -0000 On 07/02/2011, at 23:36, Ivan Voras wrote: >> OK, I wrote the data to /dev/null from USB and ran diskutil in a loop = and it doesn't drop out. >=20 > Maybe I misunderstood you and it's a different problem than what I was > experiencing; is this a better description of your problem: >=20 > 1) you have a program communicating with a USB device > 2) it reads from the device and writes to a file > 3) you experience stalls when you write the data recived from the USB > device to the file but only if the file system you're writing on is > also loaded by something else - heavy reads? >=20 > ? Yes, however CPU loading also seems to affect it. Unfortunately I don't have a useful measurement to show the problem - ie = I don't have a metric which correlates with the hardware FIFO filling = up. This makes the testing rather annoying :) -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C