[lttng-dev] Cross-domain influence on overhead

[Oestman, Fredrik]

Hi,

I've noticed the following somewhat puzzling effect on both Intel and ARM architecture computers:

If all trace events are enabled in one domain only, either kernel or user space, and there are lots of static tracepoints instrumented in the other, then these inactive tracepoints start causing overhead of about the same magnitude as if they were active, as if trace events were enabled in this domain.

Is there any obvious explanation to this behaviour?

Cheers,

Fredrik Östman

http://go.mentor.com/sourceryanalyzer/