Messages in this thread | | | Subject | Re: [RFC 1/2] softirq: Defer net rx/tx processing to ksoftirqd context | From | Mike Galbraith <> | Date | Fri, 12 Jan 2018 18:44:09 +0100 |
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On Fri, 2018-01-12 at 09:26 -0800, Linus Torvalds wrote: > On Fri, Jan 12, 2018 at 2:13 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Fri, Jan 12, 2018 at 06:23:08AM +0100, Mike Galbraith wrote: > >> > >> How would that be better than what RT used to do, and I still do for my > >> RT kernels via boot option, namely split ksoftirqd into per-softirq > >> threads. > > > > Since we mention it; one of the problems RT has is that all RX is > > through a single softirq context, which generates a priority inversion > > between devices. > > Oh, yes, that is complete and utter shit. Not acceptable at all. > > As mentioned, it really would need to be per-cpu _and_ per-softirq. > > Which is why I thought workqueues might be the thing. Whatever RT is > doing is apparently just pure and utter garbage.
Nah, a misunderstanding happened. RT that still offers full threading creates per-softirq threads per cpu. The regular trees split ksoftirqd into only two threads per cpu, one processes timer/hrtimer softriqs, the other processes the rest.
-Mike
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