Messages in this thread | | | Date | Fri, 20 Jan 2017 17:52:11 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched: Optimize pick_next_task for idle_sched_class too |
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On Fri, Jan 20, 2017 at 11:14:25AM -0500, Steven Rostedt wrote: > > OK, so I hate this patch because it makes the condition more complex, > > and while staring at what it does for code generation I couldn't for the > > life of me figure out why we care about prev->sched_class to begin with. > > I was thinking it would save on checking the rq at all, but rq is used > by pick_next_task_*() anyway, so I doubt it's much savings.
fwiw, code generation adds something like:
CMP imm32, reg JE imm8
So the overhead is not immense, something like 7-8 bytes, but still, less is more :-)
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