Messages in this thread | | | Date | Fri, 18 Nov 2016 15:23:59 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC v3 1/6] Track the active utilisation |
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On Tue, Oct 25, 2016 at 09:58:11AM -0400, Steven Rostedt wrote:
> I agree with Daniel, especially since I don't usually trust the > compiler. And the added variable is more of a distraction as it doesn't > seem to have any real purpose.
I don't think there's anything here to trust the compiler on. Either it inlines or it doesn't, it should generate 'correct' code either way.
If it doesn't inline, its a dumb compiler and it will make these dumb decisions throughout the tree and your kernel will be slow, not my problem really ;-)
That said, I agree that the single line thing is actually easier to read.
That said; there's something to be said for:
u64 running_bw;
static void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) { u64 old = dl_rq->running_bw;
dl_rq->running_bw += dl_se->dl_bw; SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ }
static void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) { u64 old = dl_rq->running_bw;
dl_rq->running_bw -= dl_se->dl_bw; SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ }
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