Messages in this thread | | | Date | Sun, 12 Sep 2004 16:17:01 +0200 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option |
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On Fri, Sep 10, 2004 at 05:34:21PM +0200, Arjan van de Ven wrote: > disabling is actually not a bad idea; hard irq handlers run for a very short
you mean hard irq handlers "should run" for a very short time. There can be slow hardware that needs a long time, and fast hardware that needs a short time, and in turn it makes perfect sense to allow nesting to give low latency to the "fast" onces, like it has always happened so far (not only in linux AFIK). Disabling nesting completely sounds a very bad idea to me, when "limiting nesting" can be achieved easily as confirmed by Alan too.
> time, but when they nest you effectively have like a semi context switch in > the middle of the work so performance suffers...
It's not nearly a semi context switch, it's like the timer irq that runs on top of userspace, not nearly the cost of a context switch (no time wasted calling the scheduler or the softirqs either for obvious reasons). - 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/
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