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    SubjectRe: [patch] softirq-2.4.5-A1
    On Sun, May 27, 2001 at 09:08:51PM +0200, Ingo Molnar wrote:
    > i took at look at your ksoftirq stuff yesterday, and i think it's
    > completely unnecessery and adds serious overhead to softirq handling. The
    > whole point of softirqs is to have maximum scalability and no
    > serialization. Why did you add ksoftirqd, would you mind explaining it?

    The only case ksoftirqd runs is when the stock kernel does the wrong
    thing and potentially delays the softirq of 1/HZ. Nothing else.

    When current kernel does the right thing ksoftirq cannot generate any
    scalability problem and furthmore ksoftirqd is a per-cpu thing so if you
    face a scalability problem with it that simply means you need to fix the
    scheduler because then it means you would face a scalability issue as
    well every time a tux thread calls schedule().

    90% of the time ksoftirqd will never run, when it runs it means you want
    to pay for a scheduler run to get it running. The price of the scheduler
    is just the price for the logic that balance the softirq load in a fair
    manner and without buggy latencies.

    Andrea
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