On Thu, Jan 11, 2018 at 12:34 PM, Dmitry Safonov <d...@arista.com> wrote: > > I could try to write a PoC for that.. > What should be the trigger to fall into workqueue? > How to tell if there're too many softirqs of the kind?
I suspect it would have to be time-based, probably using the scheduler clock. Most softirqs are really really small. So just counting them probably isn't all that meaningful, although the count is good as a fallback (as shown by the jiffy issues). The good news is that we only have a fairly small handful of softirqs, so counting/timing them separately is still mainly a pretty small array (which needs to be percpu, of course). Linus