Messages in this thread | | | Date | Wed, 31 Mar 2004 13:06:30 +0530 | From | Dipankar Sarma <> | Subject | Re: route cache DoS testing and softirqs |
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On Tue, Mar 30, 2004 at 11:29:44PM +0200, Robert Olsson wrote: > Andrea Arcangeli writes: > > I see what's going on now, yes my patch cannot help. the workload is > > simply generating too much hardirq load, and it's like if we don't use > > softirq at all but that we process the packet inside the hardirq for > > this matter. As far as RCU is concerned it's like if there a no softirq > > at all but that we process everything in the hardirq. > > > > so what you're looking after is a new feature then: > > > > 1) rate limit the hardirqs > > 2) rate limit only part of the irq load (i.e. the softirq, that's handy > > since it's already splitted out) to scheduler-aware context (not > > inside irq context anymore) > > 3) stop processing packets in irqs in the first place (NAPI or similar) > > No Andrea it pure softirq workload. Interfaces runs with irq disabled > at this load w. NAPI. Softirq's are run from spin_unlock_bh etc when > doing route lookup and GC. And the more fine-grained locking we do the > the more do_softirq's are run.
Not lookup, we don't take the lock in lookup. Probably route insertions which will happen very frequently in this case.
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