Re: [RFC PATCH 1/3] sched/core: add API for exporting runqueue clock

From: Peter Zijlstra
Date: Thu Dec 19 2019 - 04:21:06 EST


On Thu, Dec 19, 2019 at 09:29:14AM +0800, Ming Lei wrote:
> On Wed, Dec 18, 2019 at 10:51:01AM +0100, Peter Zijlstra wrote:
> > On Wed, Dec 18, 2019 at 03:19:40PM +0800, Ming Lei wrote:
> > > Scheduler runqueue maintains its own software clock that is periodically
> > > synchronised with hardware. Export this clock so that it can be used
> > > by interrupt flood detection for saving the cost of reading from hardware.
> >
> > But you don't have much, if any, guarantees the thing gets updated.
>
> Any software clock won't be guaranteed to be updated in time, however,
> they are still useful.

It still is broken, and I really don't want to expose this for whatever
reason.