From owner-freebsd-questions@FreeBSD.ORG Thu Nov 2 16:04:02 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 0A00D16A516 for ; Thu, 2 Nov 2006 16:04:02 +0000 (UTC) (envelope-from smithi@nimnet.asn.au) Received: from gaia.nimnet.asn.au (nimbin.lnk.telstra.net [139.130.45.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id D855843DA5 for ; Thu, 2 Nov 2006 16:03:43 +0000 (GMT) (envelope-from smithi@nimnet.asn.au) Received: from localhost (smithi@localhost) by gaia.nimnet.asn.au (8.8.8/8.8.8R1.4) with SMTP id DAA11162; Fri, 3 Nov 2006 03:03:21 +1100 (EST) (envelope-from smithi@nimnet.asn.au) Date: Fri, 3 Nov 2006 03:03:21 +1100 (EST) From: Ian Smith To: Anton Shterenlikht In-Reply-To: <20061101221408.9D04216A523@hub.freebsd.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Lowell Gilbert , 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 16:04:02 -0000 On Wed, 1 Nov 2006 Anton Shterenlikht wrote: > On Wed, Nov 01, 2006 at 10:49:36AM -0500, Lowell Gilbert wrote: > > * Change the printer port to polled mode. ["lptcontrol -p"] > > With this kind of hardware, it may even speed up your printing as well. > > Thanks a lot, I think it does print a bit faster. But more > importantly I see virtually no performance degradation during > printing. > > Perhaps a sentence on this should be added in section > 9.3.1.3 (Setting the Communication Mode for the Parallel Port) of > the user manual somewhere in the end of this pararaph: > > The interrupt-driven method is usually somewhat > faster but uses up a precious IRQ line. Some newer > HP printers are claimed not to work correctly in > interrupt mode, apparently due to some (not yet > exactly understood) timing problem. These printers > need polled mode. You should use whichever one works. > Some printers will work in both modes, but are > painfully slow in interrupt mode. > > and then add something like: > > On slower machines using interrupt mode might cause > significant degradation of the overall system perfor- > mance due to the interrupt service using most of the > CPU time. On such machines changing to polled mode > will balance the CPU load as well as result in > faster printing. > > Perhaps I should send a message to the documentation > list? > > anton I'm not sure if that's generally true for slower machines; you haven't said (or I missed) what sort of printer you're using, what filters you run via printcap, and such? Not one covered by the existing para? I have a 1500c, bit faster than your 1700 @300MHz, that has printed lots of large files via gs without ever seeing any significant irq 7 load nor any slowdown of the machine at all - albeit using a slow old printer. Not that I see any problem with your proposed addition. Perhaps 'On some slower machines running fast printers using interrupt mode ..' ? Cheers, Ian