From: Helge Hafting <helgehaf@aitel.hist.no>
To: "Grover, Andrew" <andrew.grover@intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Why no interrupt priorities?
Date: Fri, 27 Feb 2004 11:15:32 +0100 [thread overview]
Message-ID: <403F18C4.3080309@aitel.hist.no> (raw)
In-Reply-To: <F760B14C9561B941B89469F59BA3A84702C932F2@orsmsx401.jf.intel.com>
Grover, Andrew wrote:
>
> Is the assumption that hardirq handlers are superfast also the reason
> why Linux calls all handlers on a shared interrupt, even if the first
> handler reports it was for its device?
>
No, it is the other way around. hardirq handlers have to be superfast
because linux usually _have to_ call all the handlers of a shared irq.
The fact that one device did indeed have an interrupt for us doesn't mean
that the others didn't. So all of them have to be checked to be safe.
If this becomes a performance problem, make sure that no _busy_ irqs
are shared. The easy way is to shuffle pci cards around, or set
jumpers/switches or software controlled options. Or resort to
reprogramming the APIC in extreme cases.
Helge Hafting
next prev parent reply other threads:[~2004-02-27 10:16 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-27 1:36 Why no interrupt priorities? 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 [this message]
2004-02-27 18:32 ` Mike Fedyk
-- strict thread matches above, loose matches on Subject: below --
2004-02-27 17:44 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
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
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
2004-02-26 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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