lpt0 printer slows system response significantly
smithi at nimnet.asn.au
Thu Nov 2 16:04:02 UTC 2006
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
> Perhaps a sentence on this should be added in section
> 18.104.22.168 (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
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 ..' ?
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