lkml.org 
[lkml]   [2008]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] Re: Bad network performance over 2Gbps
    Hi!

    > [X86] IRQBALANCE: Mark as BROKEN and disable by default
    >
    > The IRQBALANCE option causes interrupts to bounce all around on SMP systems
    > quickly burying the CPU in migration cost and cache misses. Mainly affected are
    > network interrupts and this results in one CPU pegged in softirqd completely.
    >
    > Disable this option and provide documentation to a better solution (userspace
    > irqbalance daemon does overall the best job to begin with and only manual setting
    > of smp_affinity will beat it).
    >
    > Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
    >
    > ---
    >
    > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    > index 6c70fed..956aa22 100644
    > --- a/arch/x86/Kconfig
    > +++ b/arch/x86/Kconfig
    > @@ -1026,13 +1026,17 @@ config EFI
    > platforms.
    >
    > config IRQBALANCE
    > - def_bool y
    > + def_bool n

    ACK.
    > prompt "Enable kernel irq balancing"
    > - depends on X86_32 && SMP && X86_IO_APIC
    > + depends on X86_32 && SMP && X86_IO_APIC && BROKEN

    This is wrong. irqbalance works, there's nothing wrong with it; but it
    has nasty sideffects.

    > help
    > The default yes will allow the kernel to do irq load balancing.
    > Saying no will keep the kernel from doing irq load balancing.
    >
    > + This option is known to cause performance issues on SMP
    > + systems. The preferred method is to use the userspace
    > + 'irqbalance' daemon instead. See http://irqbalance.org/.
    > +

    ACK.

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


    \
     
     \ /
      Last update: 2008-04-21 15:59    [W:0.022 / U:59.844 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site