On Tue, 2018-01-23 at 11:13 +0100, Paolo Abeni wrote: > Hi, > > On Fri, 2018-01-19 at 16:46 +0100, Frederic Weisbecker wrote: > > As per Linus suggestion, this take doesn't limit the number of > > occurences > > per jiffy anymore but instead defers a vector to workqueues as soon > > as > > it gets re-enqueued on IRQ tail. > > > > No tunable here, so testing should be easier. > > > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux- > > dynticks.git > > softirq/thread-v3 > > > > HEAD: 6835e92cbd70ef4a056987d2e1ed383b294429d4 > > I tested this series in the UDP flood scenario, binding the user > space > process receiving the packets on the same CPU processing the related > IRQ, and the tput sinks nearly to 0, like before Eric's patch. > > The perf tool says that almost all the softirq processing is done > inside the workqueue, but the user space process is scheduled very > rarely, while before this series, in this scenario, ksoftirqd and the > user space process got a fair share of the CPU time.
It get a fair share of the CPU time only on some lucky platforms (maybe on the most). On other not-so-lucky platforms it was also unfair - as I've previously described by the reason of slow raising softirqs :-/ -- Thanks, Dmitry