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Is there any performance reduction to be expected from just activating trace (ftrace) functionality in the Linux kernel, but not using it at run time?

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Ftrace inserts nops into the text code, and these get turned into jumps to the tracing when enabled. There may be a slight impact on performance just by increasing the pressure on instruction cache, but all my benchmarks have kept it below the noise. There's been some cases that enabling ftrace actually improved performance. But that was probably just a fluke, where the added nops moved the hot paths into better cache localities.

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