Messages in this thread |  | | | Date | Wed, 11 Jan 2006 06:14:58 -0800 | | From | Nauman Tahir <> | | Subject | Re: Although CONFIG_IRQBALANCE is enabled IRQ's don't seem to be balanced very well |
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On 1/10/06, Jesper Juhl <jesper.juhl@gmail.com> wrote: > On 1/10/06, Martin Bligh <mbligh@mbligh.org> wrote: > > Jesper Juhl wrote: > > > On 1/10/06, Martin Bligh <mbligh@mbligh.org> wrote: > > > > > >>Josef Sipek wrote: > > >> > > >>>On Tue, Jan 10, 2006 at 12:14:42PM +0100, Jesper Juhl wrote: > > >>> > > >>> > > >>>>Do I need any userspace tools in addition to CONFIG_IRQBALANCE? > > >>> > > >>> > > >>>Last I checked, yes you do need "irqbalance" (at least that's what > > >>>the package is called in debian. > > >> > > >>Nope - you need the kernel option turned on OR the userspace daemon, > > >>not both. > > >> > > > > > > Ok, good to know. > > > > > > > > >>If you're not generating interrupts at a high enough rate, it won't > > >>rotate. That's deliberate. > > >>
What I have read is that first CPU is used more for interrupts to use the concept of maximizing cache locality. Probably kernel is optimizing this even with CONFIG option enabled.
Nauman
> > > > > > > > > Hmm, and what would count as "a high enough rate"? > > > > > > I just did a small test with thousands of ping -f's through my NIC > > > while at the same time giving the disk a good workout with tons of > > > find's, sync's & updatedb's - that sure did drive up the number of > > > interrupts and my load average went sky high (amazingly the box was > > > still fairly responsive): > > > > > > root@dragon:/home/juhl# uptime > > > 22:59:58 up 12:43, 1 user, load average: 1015.48, 715.93, 429.07 > > > > > > but, not a single interrupt was handled by CPU1, they all went to CPU0. > > > > > > Do you have a good way to drive up the nr of interrupts above the > > > treshhold for balancing? > > > > Is it HT? ISTR it was intelligent enough to ignore that. But you'd > > have to look at the code to be sure. > > > Dual Core Athlon 64 X2 4400+ > > -- > Jesper Juhl <jesper.juhl@gmail.com> > Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html > Plain text mails only, please http://www.expita.com/nomime.html > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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