Re: arch/i386/Kconfig: CONFIG_IRQBALANCE Description
From: Jamie Lokier
Date: Thu Mar 25 2004 - 14:10:10 EST
Miquel van Smoorenburg wrote:
> Is that real SMP, or hyperthreading? If it's hyperthreading, then
> it makes sense that the IRQs are not balanced.
That's unfair to the two tasks which might be running on each virtual
CPU: one of the tasks is interrupted often.
> 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.
What caused the suckage? Obviously there's a small time spend doing
the work of rebalancing, but there is no cache hit from moving an
interrupt between virtual CPUs, unlike with SMP, so why did that make
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