Editing Thread (computing) (section)

====''M'':''N'' (hybrid threading)====
''M'':''N'' maps some {{var|M}} number of application threads onto some {{var|N}} number of kernel entities,<ref name="OSConcepts" /> or "virtual processors." This is a compromise between kernel-level ("1:1") and user-level ("''N'':1") threading. In general, "''M'':''N''" threading systems are more complex to implement than either kernel or user threads, because changes to both kernel and user-space code are required{{clarify|reason=no kernel modifications are needed|date=June 2020}}. In the M:N implementation, the threading library is responsible for scheduling user threads on the available schedulable entities; this makes context switching of threads very fast, as it avoids system calls. However, this increases complexity and the likelihood of [[priority inversion]], as well as suboptimal scheduling without extensive (and expensive) coordination between the userland scheduler and the kernel scheduler.