Date: Tue, 28 Apr 1998 18:15:38 +0100 (BST) From: alan@lxorguk.ukuu.org.uk (Alan Cox) To: rgb@phy.duke.edu (Robert G. Brown) Cc: rmail@ittc.ukans.edu, aic7xxx@FreeBSD.ORG, linux-smp@vger.rutgers.edu, linux-tulip@cesdis1.gsfc.nasa.gov Subject: Re: Duration of Blocked Interrupts Message-ID: <m0yUDym-000aNhC@the-village.bc.nu> In-Reply-To: <Pine.LNX.3.96.980428113454.23254G-100000@ganesh.phy.duke.edu> from "Robert G. Brown" at Apr 28, 98 11:45:57 am
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> interrupt lock sets I noticed a very definite correlation between reads > from relatively slow devices (e.g. -- a SCSI CD-ROM) and a network > deadlockup. A lot of folks have reported and are still reporting > bizarre problems on systems with AIC cards (although mine is now totally > stable thanks to the network driver fix). Any situation doing that and locking up is a Linux code bug simple and plain. The constraint for IP service in the SMP kernel is 10mS - and you get warnings and no fatal stop if its exceeded at. > Even though my system is "stable", it could be taking quite a > performance hit, and it would be very interesting to compare the > coincidence of this sort of interrupt blocking and the "Too much work > at..." messages in fast ethernet network drivers that occur when > interrupts are stacked too deep when the driver is finally entered. 100Mbit cards have ring buffers often of about 20 frames - just servicing a messier ISA interrupt will do as much delaying as the longer AIC handler paths. Alan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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