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| /freebsd-9.3-release/sys/kern/ | ||
| H A D | sched_4bsd.c | diff 180923 Mon Jul 28 15:33:13 MDT 2008 jhb Implement support for cpusets in the 4BSD scheduler. - When a cpuset is applied to a thread, walk the cpuset to see if it is a "full" cpuset (includes all available CPUs). If not, set a new TDS_AFFINITY flag to indicate that this thread can't run on all CPUs. When inheriting a cpuset from another thread during thread creation, the new thread also inherits this flag. It is in a new ts_flags field in td_sched rather than using one of the TDF_SCHEDx flags because fork() clears td_flags after invoking sched_fork(). - When placing a thread on a runqueue via sched_add(), if the thread is not pinned or bound but has the TDS_AFFINITY flag set, then invoke a new routine (sched_pickcpu()) to pick a CPU for the thread to run on next. sched_pickcpu() walks the cpuset and picks the CPU with the shortest per-CPU runqueue length. Note that the reason for the TDS_AFFINITY flag is to avoid having to walk the cpuset and examine runq lengths in the common case. - To avoid walking the per-CPU runqueues in sched_pickcpu(), add an array of counters to hold the length of the per-CPU runqueues and update them when adding and removing threads to per-CPU runqueues. MFC after: 2 weeks |
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