Messages in this thread |  | | | Date | Sun, 27 May 2001 22:05:36 +0200 | | From | Andrea Arcangeli <> | | Subject | Re: [patch] softirq-2.4.5-A1 |
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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.
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