Messages in this thread | | | Date | Mon, 21 Apr 2008 09:38:49 -0700 | From | "Kok, Auke" <> | Subject | Re: [PATCH] Re: Bad network performance over 2Gbps |
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Pavel Machek wrote: > 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.
ok, I'm fine with taking that part out of the patch.
Ingo, want me to send an updated patch?
> >> 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. >
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