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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 11:49:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 11:49:41 -0700
commit46e0d28bdb8e6d00e27a0fe9e1d15df6098f0ffb (patch)
treed5cb66fbd85b3d5c3220aacd2d9a60f9a515903a /Documentation
parent86bbbebac1933e6e95e8234c4f7d220c5ddd38bc (diff)
parentb720342849fe685310fca01748a32730a6eca5aa (diff)
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: "The main scheduler changes in this cycle were: - NUMA balancing improvements (Mel Gorman) - Further load tracking improvements (Patrick Bellasi) - Various NOHZ balancing cleanups and optimizations (Peter Zijlstra) - Improve blocked load handling, in particular we can now reduce and eventually stop periodic load updates on 'very idle' CPUs. (Vincent Guittot) - On isolated CPUs offload the final 1Hz scheduler tick as well, plus related cleanups and reorganization. (Frederic Weisbecker) - Core scheduler code cleanups (Ingo Molnar)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) sched/core: Update preempt_notifier_key to modern API sched/cpufreq: Rate limits for SCHED_DEADLINE sched/fair: Update util_est only on util_avg updates sched/cpufreq/schedutil: Use util_est for OPP selection sched/fair: Use util_est in LB and WU paths sched/fair: Add util_est on top of PELT sched/core: Remove TASK_ALL sched/completions: Use bool in try_wait_for_completion() sched/fair: Update blocked load when newly idle sched/fair: Move idle_balance() sched/nohz: Merge CONFIG_NO_HZ_COMMON blocks sched/fair: Move rebalance_domains() sched/nohz: Optimize nohz_idle_balance() sched/fair: Reduce the periodic update duration sched/nohz: Stop NOHZ stats when decayed sched/cpufreq: Provide migration hint sched/nohz: Clean up nohz enter/exit sched/fair: Update blocked load from NEWIDLE sched/fair: Add NOHZ stats balancing sched/fair: Restructure nohz_balance_kick() ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1d1d53f85ddd..50b9837e985b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1766,6 +1766,17 @@
nohz
Disable the tick when a single task runs.
+
+ A residual 1Hz tick is offloaded to workqueues, which you
+ need to affine to housekeeping through the global
+ workqueue's affinity configured via the
+ /sys/devices/virtual/workqueue/cpumask sysfs file, or
+ by using the 'domain' flag described below.
+
+ NOTE: by default the global workqueue runs on all CPUs,
+ so to protect individual CPUs the 'cpumask' file has to
+ be configured manually after bootup.
+
domain
Isolate from the general SMP balancing and scheduling
algorithms. Note that performing domain isolation this way