Date: Tue, 28 Apr 1998 09:03:53 -0700 From: Matthew Jacob <mjacob@feral.com> To: "Robert G. Brown" <rgb@phy.duke.edu> Cc: Mail Receiver <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: <3545FDE9.3710DBCD@feral.com> References: <Pine.LNX.3.96.980428113454.23254G-100000@ganesh.phy.duke.edu>
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Yes, this might be true. The only problem here is that in looking over the version of the linux AIC stuff I have, it *does* go to the effort to restore_flags in a number of places so it doesn't lock out *everyone* for long periods of time. That is, it locks out all interrupts briefly (mostly to mark that it's servicing an interrupt), and then it runs a while w/o. It blocks interrupts checking for sequencer conditions (usually error cases), and also while cleaning up after finishing. It then unblocks interrupts before calling the linux midlayer to complete (well done, actually). By "blocking/unblocking" I mean higher level interrupts. I could easily believe that if your network cards are at lower or same irqs they might starve. But short of doing some more clever thread managment, or doing an explicit sti() in the SCSI midlayer, I doubt that this is easily fixable. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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