Date: Sun, 9 Apr 2006 22:55:32 -0700 From: Oliver Iberien <oliver-forward@charter.net> To: freebsd-questions@freebsd.org Subject: Re: Setting max interrupts per second (WAS printing on firefox) Message-ID: <200604092255.33239.oliver-forward@charter.net> In-Reply-To: <20060408132247.1df00a38@localhost> References: <200604071332.57717.oliver-forward@charter.net> <20060408132247.1df00a38@localhost>
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On Saturday 08 April 2006 04:22, Fabian Keil wrote: > Oliver Iberien <oliver-forward@charter.net> wrote: > > [snip] The printer (Xerox N17, local, > > parallel port) started cycling through waiting-processing-waiting > > messages. Rebooting, I saw a message about an IRQ storm on the > > printer port being "throttled". Killing the job took care of this. > > [snip] > > The default value of hw.intr_storm_threshold is easily reached > by a printer connected through the parallel port. > > Have a look at: <http://www.lemis.com/grog/diary-dec2005.html#8>. > > Fabian Thanks for this. Here's the relevent text from that weblog: > As a result, once more harnessed my veteran HP LaserJet 6MP to echunga. > Printing went at a snail's pace. Finally I discovered the message: > Interrupt storm detected on "irq7: lpt0"; throttling interrupt source > > It proved to be a new interrupt throttling feature in the system: the > sysctl variable hw.intr_storm_threshold sets the maximum number of > interrupts per second on any interrupt level. The default value is 500, > woefully inadequate for a PostScript printer on a parallel port, which can > generate over 100,000 interrupts a second. Fixed that: === root@echunga > (/dev/ttyp1) ~ 130 -> sysctl hw.intr_storm_threshold > hw.intr_storm_threshold: 500 > === root@echunga (/dev/ttyp1) ~ 131 -> sysctl hw.intr_storm_threshold=200000 > hw.intr_storm_threshold: 500 -> 200000 > > Unfortunately, this effectively disables the interrupt storm detection > system-wide. The values should be per interrupt. Does anyone have any idea what an optimum number would be? Oliver
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