Messages in this thread | | | Date | Wed, 26 Nov 2003 12:09:29 -0500 (EST) | From | Zwane Mwaikambo <> | Subject | Re: [PATCH] irq_balance does not make sense with HT but single physical CPU |
| |
On Wed, 26 Nov 2003, Kai Bankett wrote:
> But anyways if physical_balance is set to 1 that won´t prevent anything > from running through/sleeping in the kernel_thread-loop. > The kernel_thread(balance_irq ...) later on will be started/will run not > matter what physical_balance says.
Yes that only stops balancing across physical packages when there are none. But there might be a performance improvement for light (cache footprint wise) high frequency interrupt handling which stays affined to one logical processor.
> Do there exist any cases where smp_siblings are created without > HyperThreading ? (As far as I remember it´s only incremented/used on > i386 hyperthreaded architectures - but not 100% sure)
This is all i386 specific code so we don't have to care about other architectures in here.
> -> At least the if has to look like : > > ... > if (smp_num_siblings > 2 && !cpus_empty(tm)) > physical_balance = 1; > ...
smp_num_siblings won't be greater than 2 with current i386 processors, it's not a total sibling count, but a per physical package count. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |