From owner-freebsd-questions@FreeBSD.ORG Thu Nov 2 06:37:33 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 76D2116A40F for ; Thu, 2 Nov 2006 06:37:33 +0000 (UTC) (envelope-from tedm@toybox.placo.com) Received: from mail.freebsd-corp-net-guide.com (mail.web-strider.com [65.75.192.90]) by mx1.FreeBSD.org (Postfix) with ESMTP id E66B243D5C for ; Thu, 2 Nov 2006 06:37:32 +0000 (GMT) (envelope-from tedm@toybox.placo.com) Received: from coolf89ea26645 (nat-rtr.freebsd-corp-net-guide.com [65.75.197.130]) by mail.freebsd-corp-net-guide.com (8.11.1/8.11.1) with SMTP id kA26bJx09072; Wed, 1 Nov 2006 22:37:19 -0800 (PST) (envelope-from tedm@toybox.placo.com) Message-ID: <036401c6fe49$3ba45150$3c01a8c0@coolf89ea26645> From: "Ted Mittelstaedt" To: , References: <20061101000426.GA60303@mech-aslap33.men.bris.ac.uk> <45485490.D5trgMIQ1JYsEyMX%perryh@pluto.rain.com> Date: Wed, 1 Nov 2006 22:36:30 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1807 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1807 Cc: freebsd-questions@freebsd.org Subject: Re: lpt0 printer slows system response significantly X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Nov 2006 06:37:33 -0000 You can also get a faster CPU, more cycles available for servicing interrupts. Ted ----- Original Message ----- From: To: Cc: Sent: Wednesday, November 01, 2006 12:02 AM Subject: Re: lpt0 printer slows system response significantly > > PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND > > 18 root 1 -60 -179 0K 8K *Giant 15:09 77.05% irq7: lpt0 > > 11 root 1 171 52 0K 8K RUN 48.0H 11.13% idle > > The interrupt service for the parallel port is using over 3/4 of > the CPU, and half of the rest is "idle". > > I take it this is a laser printer, which can consume bytes from the > parallel port as fast as the processor can send them. Top-of-head > dump of ways to cut down on the interrupt traffic: > > * Get a DMA-capable parallel port (supposing such exist, and FreeBSD > supports them); > > * Move the printer to a network connection or dedicated print server; > > * Somehow tell the printer not to receive so quickly. > > Alternatively, one possible way to handle that sort of interrupt > load without bogging down is to get a second CPU and run SMP, so > you've still got a CPU available for tasks when one is swamped > with interrupt traffic. > > The other thing that *might* help some is more RAM, if it happens > that the idle time is caused by page wait due to the set of active > threads needing more RAM than you have, but this will at best get > your tasks up from 1/9 of the CPU to 2/9. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" >