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authorFrederic Weisbecker <frederic@kernel.org>2018-02-21 05:17:29 +0100
committerIngo Molnar <mingo@kernel.org>2018-02-21 09:49:10 +0100
commit083c6eeab2cc13894618d188b854f2fc6b5b2303 (patch)
tree6b35326abba090c1167c30c035c4312d484abda6 /Documentation/admin-guide
parentsched/nohz: Remove the 1 Hz tick code (diff)
downloadlinux-083c6eeab2cc13894618d188b854f2fc6b5b2303.tar.xz
linux-083c6eeab2cc13894618d188b854f2fc6b5b2303.zip
sched/isolation: Update nohz documentation to explain tick offload
Update the documentation to reflect the 1Hz tick offload changes. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1519186649-3242-8-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/admin-guide')
-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