CVSROOT: /cvs Module name: src Changes by: kette...@cvs.openbsd.org 2016/03/28 14:49:59
Modified files: sys/kern : kern_synch.c syscalls.master Log message: Make sure that a thread that calls sched_yield(2) ends up on the run queue behind all other threads in the process by temporarily lowering its priority. This isn't optimal but it is the easiest way to guarantee that we make progress when we're waiting on an other thread to release a lock. This results in significant improvements for processes that suffer from lock contention, most notably firefox. Unfortunately this means that sched_yield(2) needs to grab the kernel lock again. All the hard work was done by mpi@, based on observations of the behaviour of the BFS scheduler diff by Michal Mazurek. ok deraadt@