Re: [PATCH] sched/rt: Do not do push/pull when there is only one CPU
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2017-12-02 17:12:57
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On Sat, 2 Dec 2017 13:53:31 +0100 Sebastian Andrzej Siewior [off-list ref] wrote:
what about a check next to sched_feat(RT_PUSH_IPI)? I don't know if this is a hot path or not (due to bitmap_weight). If it is, then I would suggest something like a jump-label which is enabled if more than one CPU has been enabled on boot.
Yeah I didn't like that because of the overhead. But I was being optimistic that the cpu weight function would be a nit to the actual pull logic. But I have a better plan. I would like to disable RT_PUSH_IPI, but that's a sched feature and that is a constant if we build without sched debugging. v2 coming up. -- Steve