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SubjectRe: [RFC 1/2] softirq: Defer net rx/tx processing to ksoftirqd context
On Tue, Jan 9, 2018 at 5:36 AM, Dmitry Safonov <dima@arista.com> wrote:
> Warning: Not merge-ready
>
> I. Current workflow of ksoftirqd.
> Softirqs are processed in the context of ksoftirqd iff they are
> being raised very frequently. How it works:
> do_softirq() and invoke_softirq() deffer pending softirq iff
>

...

>
> Note, that I tested in VMs and I've found that if I produce more
> hw irqs on the host, than the results for master are not that
> dramatically bad, but still much worse then with RFC.
> By that reason I have qualms if my test's results are correct.

Note that deferring all NET RX/TX to ksoftirqd is going to
dramatically hurt tail latencies.

You really should test with RPC like workloads (netperf -t TCP_RR) and
hundred of threads per cpu :/

It seems we are going to revert/adapt 4cd13c21b2 , not defer more
stuff to ksoftirqd.

Thanks

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