On 06/10/2016 06:11 PM, Steven Rostedt wrote:

quoted

It is true that in RT we don't have such a limit like in !RT. You would
need to use __raise_softirq_irqoff_ksoft() instead the normal or +
wakeup() since you may have timers pending and those need to go to the
"other" ksoftirqd.
But then I don't see much change. ksoftirqd runs now at SCHED_OTHER so
it will end up on the CPU right away unless there other tasks that need
the CPU. So the scheduler will balance it the same way. The only change
will be that softirqs which are processed in context of any application
for more than two jiffies will be moved to ksoftirqd. This could be a
win.

We actually triggered a starvation due to this. I was just seeing if
Alison hit the same issue we did in our tests.

Okay. Didn't get this information from him. But this is only because
the softirqs not running in ksoftirqd, right?

-- Steve

Sebastian