Messages in this thread |  | | | Date | Mon, 26 May 2003 19:10:02 -0700 | | From | William Lee Irwin III <> | | Subject | Re: userspace irq balancer |
| |
William Lee Irwin III <wli@holomorphy.com> wrote: >> In >> the userspace implementation the reprogramming is done infrequently >> enough to make even significant cost negligible; in-kernel the cost >> is entirely uncontrolled and the rate of reprogramming unlimited.
On Mon, May 26, 2003 at 06:59:20PM -0700, Andrew Morton wrote: > eh? > #define MAX_BALANCED_IRQ_INTERVAL (5*HZ) > #define MIN_BALANCED_IRQ_INTERVAL (HZ/2)
The number of interrupt sources on a system ends up scaling this up to numerous IO-APIC RTE reprograms and ioapic_lock acquisitions per-second (granted, with a 5s timeout between reprogramming storms) where it competes against IO-APIC interrupt acknowledgements.
Making the lock per- IO-APIC would at least put a bound on the number of competitors mutually interfering with each other, but a tighter bound on the amount of work than NR_IRQS would be more useful than that.
-- wli - 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/
|  |