Re: lpt0 printer slows system response significantly
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 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
On Fri, Nov 03, 2006 at 03:03:21AM +1100, Ian Smith wrote: 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. 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. 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 That's interesting. I use lj2100 with apsfilter via printcap. aps1|lp|laserjet;r=1200x1200;q=medium;c=gray;p=a4;m=auto:\ :lp=/dev/lpt0:\ :if=/usr/local/etc/apsfilter/basedir/bin/apsfilter:\ thanks anton ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
PID USERNAME THR PRI NICE SIZERES STATETIME WCPU COMMAND 18 root1 -60 -179 0K 8K *Giant 15:09 77.05% irq7: lpt0 11 root1 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 [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
On Wed, Nov 01, 2006 at 12:02:24AM -0800, [EMAIL PROTECTED] wrote: PID USERNAME THR PRI NICE SIZERES STATETIME WCPU COMMAND 18 root1 -60 -179 0K 8K *Giant 15:09 77.05% irq7: lpt0 11 root1 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: yes, it is lj2100. * Somehow tell the printer not to receive so quickly. how can I do this? thanks anton ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
[EMAIL PROTECTED] writes: PID USERNAME THR PRI NICE SIZERES STATETIME WCPU COMMAND 18 root1 -60 -179 0K 8K *Giant 15:09 77.05% irq7: lpt0 11 root1 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. * Change the printer port to polled mode. [lptcontrol -p] With this kind of hardware, it may even speed up your printing as well. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
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 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
* Somehow tell the printer not to receive so quickly. how can I do this? I have no idea how to do it, or if it is even possible, which is why I said somehow. You could check the printer's manual to see if it has such a setting. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: lpt0 printer slows system response significantly
You can also get a faster CPU, more cycles available for servicing interrupts. Ted - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: freebsd-questions@freebsd.org Sent: Wednesday, November 01, 2006 12:02 AM Subject: Re: lpt0 printer slows system response significantly PID USERNAME THR PRI NICE SIZERES STATETIME WCPU COMMAND 18 root1 -60 -179 0K 8K *Giant 15:09 77.05% irq7: lpt0 11 root1 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 [EMAIL PROTECTED] ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
