On Wed, 12 Dec 2018 at 10:46, Peter Zijlstra <pet...@infradead.org> wrote: > > On Tue, Dec 11, 2018 at 10:51:48AM +0100, Rafael J. Wysocki wrote: > > On Mon, Dec 10, 2018 at 11:51 PM Peter Zijlstra <pet...@infradead.org> > > wrote: > > > > Dunno; it could be cold cachelines, at which point it can be fairly > > > expensive. Also, being stuck with API is fairly horrible if you want to > > > 'fix' it. > > > > All of the cache lines involved should've been touched earlier in this > > code path by the governor. At least menu and the new one both touch > > them. > > > > The API part I'm not too worried about. I know it is useful and two > > other people have told that to me already. :-) > > Like said on IRC; I mostly wanted to raise the issue of overhead due to > stats and ABI -- it's something I've been bitten by too many times :/ > > If you're confident you're hitting the same lines with the already > extant accouning (time and usage) and you cannot make the whole lot > conditional because of ABI (bah) then I'll not stand in the way here. > > I agree the numbers are useful, I'm just weary of overhead.
I tend to agree. So then why not move this to debugfs, it seems like it's really there it belongs. No? Kind regards Uffe
