On Tue, Dec 15, 2015 at 05:45:16PM +0000, Mark Brown wrote: > On Tue, Dec 15, 2015 at 05:28:37PM +0000, Mark Rutland wrote: > > On Tue, Dec 15, 2015 at 05:17:13PM +0000, Mark Brown wrote: > > > > Obviously people are going to get upset if we introduce performance > > > regressions - but that's true always, we can also introduce problems > > > with numbers people have put in DT. It seems like it'd be harder to > > > manage regressions due to externally provided magic numbers since > > > there's inherently less information there. > > > It's certainly still possible to have regressions in that case. Those > > regressions would be due to code changes in the kernel, given the DT > > didn't change. > > > I'm not sure I follow w.r.t. "inherently less information", unless you > > mean trying to debug without access to that DTB? > > If what the kernel knows about the system is that it's got a bunch of > cores with numbers assigned to them then all it's really got is those > numbers. If something changes that causes problems for some systems > (eg, because the numbers have been picked poorly but in a way that > happened to work well with the old code) that's not a lot to go on, the > more we know about the system the more likely it is that we'll be able > to adjust the assumptions in whatever new thing we do that causes > problems for any particular systems where we run into trouble. Regardless of where the numbers live (DT or kernel), all we have are numbers. I can see that changing the in-kernel numbers would be possible when modifyign the DT is not, but I don't see how that gives you more information. Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
