Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 12 Mar 2003 11:11:16 +0100 | Subject | Re: is irq smp affinity good for anything? | From | uaca@alumni ... |
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On Tue, Mar 11, 2003 at 08:48:59PM -0500, Mark Hahn wrote: > > I did not expect to increase global latency to these results... > > and neither to increase latency in the CPU that's receiving > > just one interrupt! > > but isn't that just a cache effect? that is, you're keeping > all cpus busy (caches too) with user-space, so when the interrupt > comes in, a bound interrupt has no choice, even if the cache > is busy with userspace. Hi
first of all thanks for your reply,
I think that user space code always has to make the best use of cache as it can... in other words, i don't want to use a cpu exclusively for a device that delivers 6000 ints/second
I bound an irq to a cpu because I thought that:
as spin_irq_locks just disables interrupts locally I should get better latency that just one ISR on that particular cpu could at least reduce a little the number of times that interrupts get disabled on that cpu
... that was my reasoning...
but latency gets worse... that's not comphrensible for me...
Ulisses
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