On Wed, Jun 6, 2012 at 8:04 AM, tip-bot for Suresh Siddha <suresh.b.siddha@xxxxxxxxx> wrote: > Commit-ID: 0b8255e660a0c229ebfe8f9fde12a8d4d34c50e0 > Gitweb: http://git.kernel.org/tip/0b8255e660a0c229ebfe8f9fde12a8d4d34c50e0 > Author: Suresh Siddha <suresh.b.siddha@xxxxxxxxx> > AuthorDate: Mon, 21 May 2012 16:58:02 -0700 > Committer: Ingo Molnar <mingo@xxxxxxxxxx> > CommitDate: Wed, 6 Jun 2012 09:51:22 +0200 > > x86/x2apic/cluster: Use all the members of one cluster specified in the smp_affinity mask for the interrupt destination > > If the HW implements round-robin interrupt delivery, this > enables multiple cpu's (which are part of the user specified > interrupt smp_affinity mask and belong to the same x2apic > cluster) to service the interrupt. > > Also if the platform supports Power Aware Interrupt Routing, > then this enables the interrupt to be routed to an idle cpu or a > busy cpu depending on the perf/power bias tunable. > > We are now grouping all the cpu's in a cluster to one vector > domain. So that will limit the total number of interrupt sources > handled by Linux. Previously we support "cpu-count * > available-vectors-per-cpu" interrupt sources but this will now > reduce to "cpu-count/16 * available-vectors-per-cpu". with this patch, will waste/hide several irq vector on some cpus. for example: very beginning after boot, one irq will have vector from 16 cpus of same cluster. later if user using irq affinity change to one cpu only. cfg->domain will be not changed, but ioapic or irte will be confined to one cpu. because mask is used for new dest_id. *dest_id = apic->cpu_mask_to_apicid_and(mask, cfg->domain); all other 15 cpu vector are wasted or hided. Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html