From: Tim Hockin <thockin@hockin.org>
To: Matt Mackall <mpm@selenic.com>
Cc: "Grover, Andrew" <andrew.grover@intel.com>,
Helge Hafting <helgehaf@aitel.hist.no>,
linux-kernel@vger.kernel.org
Subject: Re: Why no interrupt priorities?
Date: Fri, 27 Feb 2004 11:09:14 -0800 [thread overview]
Message-ID: <20040227190914.GA21737@hockin.org> (raw)
In-Reply-To: <20040227185555.GJ3883@waste.org>
On Fri, Feb 27, 2004 at 12:55:55PM -0600, Matt Mackall wrote:
> Let's imagine you have n sources simultaneously interrupting on a
> given descriptor. Check the first, it's happening, acknowledge it,
> exit, notice interrupt still asserted, check the first, nope, check
> the second, yep, exit, etc. By the time we've made it to the nth ISR,
> we've banged on the first one n times, the second n-1 times, etc. In
> other words, early chain termination has an O(n^2) worst case.
That is a pretty pathological worst case, and n is (almost?) always small.
I don't know if it would make a lick of difference, or if it is worth the
risk. Someone who has a lot of shared interrupts ought to try it.
next prev parent reply other threads:[~2004-02-27 19:12 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-27 17:44 Why no interrupt priorities? Grover, Andrew
2004-02-27 18:15 ` Chris Friesen
2004-02-27 18:42 ` Richard B. Johnson
2004-02-27 19:42 ` Michael Frank
2004-02-27 19:11 ` Michael Frank
2004-02-27 18:55 ` Matt Mackall
2004-02-27 19:09 ` Tim Hockin [this message]
2004-02-27 20:29 ` Matt Mackall
2004-02-27 19:19 ` Michael Frank
2004-02-27 20:53 ` Jesse Pollard
2004-02-29 9:43 ` Michael Frank
2004-03-01 16:57 ` Jesse Pollard
2004-03-01 17:35 ` Michael Frank
2004-03-02 15:25 ` Jesse Pollard
-- strict thread matches above, loose matches on Subject: below --
2004-02-27 11:37 Etienne Lorrain
2004-02-27 13:24 ` Michael Frank
[not found] <mailman.1077822002.21081.linux-kernel2news@redhat.com>
2004-02-27 8:00 ` Pete Zaitcev
2004-02-27 1:36 Grover, Andrew
2004-02-27 3:02 ` Randy.Dunlap
2004-02-29 8:32 ` Michael Frank
2004-02-29 8:36 ` Arjan van de Ven
2004-02-29 9:52 ` Michael Frank
2004-02-27 5:32 ` Benjamin Herrenschmidt
2004-02-27 6:26 ` Michael Frank
2004-02-27 6:46 ` Benjamin Herrenschmidt
2004-02-27 9:05 ` Russell King
2004-02-27 13:31 ` Michael Frank
2004-02-27 13:45 ` Richard B. Johnson
2004-02-27 13:50 ` Russell King
2004-02-27 14:51 ` Michael Frank
2004-02-27 7:25 ` Arjan van de Ven
2004-02-27 10:15 ` Helge Hafting
2004-02-27 18:32 ` Mike Fedyk
2004-02-26 23:47 Albert Cahalan
2004-02-26 19:05 Tim Bird
2004-02-26 19:39 ` Richard B. Johnson
2004-02-26 21:02 ` Tim Bird
2004-02-26 21:30 ` Arjan van de Ven
2004-02-26 22:21 ` Mark Gross
2004-02-27 7:14 ` Arjan van de Ven
2004-02-27 11:27 ` Ingo Oeser
2004-02-27 11:52 ` Arjan van de Ven
2004-02-27 13:23 ` Richard B. Johnson
2004-02-27 12:04 ` Christoph Hellwig
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