On Tue, Mar 29, 2016 at 04:29:07PM -0400, Steven Rostedt wrote: > On Tue, 29 Mar 2016 22:11:45 +0200 > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > > > Yes, we don't want to get rid of the old one. But it shouldn't break > > > anything if we extend it. I'm thinking of extending it with a dynamic > > > array to store the deadline task values (runtime, period). And for non > > > deadline tasks, the array would be empty (size zero). I think that > > > could be doable and maintain backward compatibility. > > > > Why the complexity? Why not just tack those 32 bytes on and get on with > > life? > > 32 bytes that are zero and meaningless for 99.999% of scheduling? > > The scheduling tracepoint is probably the most common tracepoint used, > and one of the frequent ones. 32bytes of wasted space per event can > cause a lot of tracing to be missed. Typically you don't schedule _that_ often. Sure if you run pipe-bench and hit ~.5e6 ctx/s its ~15M/s extra. But building a kernel gets me ~.5e3 ctx/s (per cpu), at which rate its 15K/s extra. But sure, if you want to make it fancy have at. -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
