On Thu, Nov 19, 2020 at 11:52:28AM +0800, Yafang Shao wrote: > The 'cfs_rq' in these helpers is only used to get the rq_clock, so we > can pass the rq_clock directly. After that, these helpers can be used by > all sched class. > > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> This introduces overhead in the general case even when schedstats is disabled. Previously, update_stats_wait_start was a static inline so function call overhead was avoided and schedstat_enabled() meant the overhead was negligible. As it's now a function call, the cost of the function entry/exit will be unconditionally hit regardless of intrest in schedstat. Regardless of the merit of adding schedstats for RT, the overhead of schedstats when stats are disabled should remain the same with the static branch check done in an inline function. -- Mel Gorman SUSE Labs
