Date: Mon, 02 Aug 2004 14:10:29 +0200 From: Ian FREISLICH <if@hetzner.co.za> To: "Willem Jan Withagen" <wjw@withagen.nl> Cc: current@FreeBSD.ORG Subject: Re: LPT interruptstorm Message-ID: <E1Brbe9-000Lok-00@hetzner.co.za> In-Reply-To: Message from "Willem Jan Withagen" <wjw@withagen.nl> <007601c47888$1cf15580$471b3dd4@digiware.nl>
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"Willem Jan Withagen" wrote: > From: "Ian FREISLICH" <if@hetzner.co.za> > > "Willem Jan Withagen" wrote: > > > Hi, > > > > > > Must be a FAQ, but I did not find anything ... > > > > > > When wanting to print thru /dev/lpt0 the kernel now starts to > > > complain about interruptstorms. Something I can imagine, since > > > printing can generate > 1000 ints/sec. Problem is that the > > > current document (500k) is now printed at 100 interrupts/sec. > > > > > > That's going to take some time.... > > > How do I prevent this from happening? > > > > /etc/sysctl.conf: hw.intr_storm_threshold=2000 > > > > OR > > > > /boot/device.hints: hint.ppc.0.flags="0x8" > > > > Make sure your bios is set to ecp/epp for the printer port, or the > > second option will fail. A couple of people around here have also > > suggested 'lptcontrol -e', but every time I've tried that (even with > > lpd stopped) I get 'lptcontrol: open: Device busy'. I'm not sure > > what keeps the printer port open other than lpd. > > Setting the sysctl worked. But now watching it with sysstat, I see > that the interrupts go up as high as 65.000 ???? Yes, I was seeing ~43000/second on my PII. If you set the hint, I think it will use DMA to do the transfer with periodic interrupts to fill the buffer. Ian -- Ian Freislich
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