Messages in this thread | | | Date | Mon, 21 Nov 2016 10:06:54 -0800 | From | Andi Kleen <> | Subject | Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! |
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> And a popf can be much more expensive than any of these. You should > know, not all instructions are equal. > > Using perf, I've seen popf take up almst 30% of a function the size of > this.
In any case it's a small fraction of the 600+ instructions which are currently executed for every enabled trace point.
If ftrace was actually optimized code this would make some sense, but it clearly isn't ...
-Andi
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