Messages in this thread | | | Date | Tue, 22 Apr 2008 01:07:35 -0400 | From | Bill Fink <> | Subject | Re: [PATCH] Re: Bad network performance over 2Gbps |
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On Thu, 17 Apr 2008, Kok, Auke wrote:
> [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 > prompt "Enable kernel irq balancing" > - depends on X86_32 && SMP && X86_IO_APIC > + depends on X86_32 && SMP && X86_IO_APIC && BROKEN > help > The default yes will allow the kernel to do irq load balancing. > Saying no will keep the kernel from doing irq load balancing.
Since you're changing the default setting, shouldn't the above be changed to:
Saying yes will allow the kernel to do irq load balancing. The default 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/. > + > config SECCOMP > def_bool y > prompt "Enable seccomp to safely compute untrusted bytecode"
-Bill
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