From: "Miquel van Smoorenburg" <miquels@cistron.nl>
Subject: Re: arch/i386/Kconfig: CONFIG_IRQBALANCE Description
Date: Tue, 23 Mar 2004 21:30:13 +0000 (UTC)
Organization: Cistron Group
Message-ID: <c3qa94$qhi$1@news.cistron.nl>
References: <1079996577.6595.19.camel@bach> <16480.28882.388997.71072@gargle.gargle.HOWL>
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Originator: miquels@cistron-office.nl (Miquel van Smoorenburg)
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In article <16480.28882.388997.71072@gargle.gargle.HOWL>,
John Stoffel <stoffel@lucent.com> wrote:
>
>And hey, under 2.6.5-rc2-mm1, it doens't seem to do anything:
>
>  > zcat /proc/config.gz | grep IRQ
>  CONFIG_IRQBALANCE=y
>  CONFIG_IDEPCI_SHARE_IRQ=y
>
>  > cat /proc/interrupts 
>	     CPU0       CPU1       
>    0:   46272316        487    IO-APIC-edge  timer
>    1:        376          0    IO-APIC-edge  i8042
>   16:      46770          3   IO-APIC-level  ide2, ide3, ehci_hcd
>   17:     307832          1   IO-APIC-level  eth0
>   18:     118258          1   IO-APIC-level  aic7xxx, aic7xxx, ohci_hcd
>  LOC:   46279245   46279281 

Is that real SMP, or hyperthreading? If it's hyperthreading, then
it makes sense that the IRQs are not balanced.

In fact I have a server on which the IRQ balancing code does
balance over the 2 virtual CPUs by accident (still have to debug
what goes wrong and file a proper bug report) and as a result
performance sucked until I turned it off.

Mike.
-- 
Netu, v qba'g yvxr gur cynvagrkg :)

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