Date: Tue, 22 Sep 1998 05:53:55 -0400 (EDT) From: System Administrator <admin@intergrafix.net> To: Doug Ledford <dledford@dialnet.net> Cc: aic7xxx@FreeBSD.ORG Subject: Re: IRQ deadlocks Message-ID: <Pine.LNX.4.03.9809220547200.29233-100000@athena.intergrafix.net> In-Reply-To: <3606A37E.CD8902A2@dialnet.net>
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ok, it froze this morning with 2.0.35 and pre10. I tried patching pre10
against 2.0.33 but it failed.
I did however discover something that may be relevant. Normally with SMP
you enable RTC support in the kernel. in linux/Documentation/rtc.txt
it says:
"
At high frequencies, or under high loads, the user process should check
the number of interrupts received since the last read to determine if
there has been any interrupt "pileup" so to speak. Just for reference, a
typical 486-33 running a tight read loop on /dev/rtc will start to suffer
occasional interrupt pileup (i.e. > 1 IRQ event since last read) for
frequencies above 1024Hz. So you really should check the high bytes
of the value you read, especially at frequencies above that of the
normal timer interrupt, which is 100Hz.
"
procinfo shows for rtc:
irq 0: 216740 timer irq 8: 0 + rtc
then rtc.txt says:
"
Also, if the kernel time is synchronized with an external source, the
kernel will write the time back to the CMOS clock every 11 minutes. In
the process of doing this, the kernel briefly turns off RTC periodic
interrupts, so be aware of this if you are doing serious work. If you
don't synchronize the kernel time with an external source (via ntp or
whatever) then the kernel will keep its hands off the RTC, allowing you
exclusive access to the device for your applications.
"
I sync my time via caldera's time server with xntpd/ntpdate. Maybe this is
messing with it? Maybe I should just turn the external sync with caldera
off and see what happens?
-Tony
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Anthony J. Biacco Network Administrator/Engineer
admin@intergrafix.net Intergrafix Internet Services
"The best way to predict the future, is to invent it."
http://cygnus.ncohafmuta.com http://www.intergrafix.net
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