[email protected] writes: > From: Kan Liang <[email protected]> > > The rough overhead rate can be caculated by the sum of all kinds of > overhead / elapsed time. > If the overhead rate is higher than 10%, warning the user.
Thinking about this more: this is comparing the cost of a single CPU to the total wall clock time. This isn't very good and can give confusing results with many cores. Perhaps we need two separate metrics here: - cost of perf record on its CPU (or later on if it gets multi threaded more multiple). Warn if this is >50% or so. - average perf collection overhead on a CPU. The 10% threshold here seems appropiate. -Andi
