Date: Mon, 27 Apr 1998 22:14:45 -0500 From: Doug Ledford <dledford@dialnet.net> To: Mail Receiver <rmail@ittc.ukans.edu> Cc: aic7xxx@FreeBSD.ORG Subject: Re: Duration of Blocked Interrupts Message-ID: <354549A5.3F52E18F@dialnet.net> References: <Pine.LNX.3.95.980427202026.30468B-100000@hegel.ittc.ukans.edu>
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Mail Receiver wrote: > > We're doing some research into what parts of the Linux kernel block > interrupts for the longest periods of time (as part of a real-time > project). Surprise, surprise, we found the disk subsystem to be one of > the biggest contributors. In particular, we've found that the aic7xxx_isr > routine can block interrupts for periods of as long as 400+ microseconds What version of the aic7xxx driver were you testing? I wouldn't be suprised if the latest versions can do exactly this. There are things that can be done to get around this problem in 2.0.x, but there won't be much we can do about it at all in 2.1.x and probably 2.2.x due to the spin lock semantics and requirements. I would have to consider the consequences of changing things around in the 2.1.x driver before I would recommend the changes I'm thinking of. -- Doug Ledford <dledford@dialnet.net> Opinions expressed are my own, but they should be everybody's. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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