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authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-14 13:03:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-14 13:03:00 -0700
commitbd9a3dba185ce6701b41f0341470d3f53bbbbaed (patch)
tree176e732da067328e29582ed30c91e25ecbaf2c4b /Documentation
parentMerge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux (diff)
parentsched/psi: Per-cgroup PSI accounting disable/re-enable interface (diff)
downloadlinux-dev-bd9a3dba185ce6701b41f0341470d3f53bbbbaed.tar.xz
linux-dev-bd9a3dba185ce6701b41f0341470d3f53bbbbaed.zip
Merge tag 'sched-psi-2022-10-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull PSI updates from Ingo Molnar: - Various performance optimizations, resulting in a 4%-9% speedup in the mmtests/config-scheduler-perfpipe micro-benchmark. - New interface to turn PSI on/off on a per cgroup level. * tag 'sched-psi-2022-10-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/psi: Per-cgroup PSI accounting disable/re-enable interface sched/psi: Cache parent psi_group to speed up group iteration sched/psi: Consolidate cgroup_psi() sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressure sched/psi: Remove NR_ONCPU task accounting sched/psi: Optimize task switch inside shared cgroups again sched/psi: Move private helpers to sched/stats.h sched/psi: Save percpu memory when !psi_cgroups_enabled sched/psi: Don't create cgroup PSI files when psi_disabled sched/psi: Fix periodic aggregation shut off
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 7bcfb38498c6..dc254a3cb956 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -976,6 +976,29 @@ All cgroup core files are prefixed with "cgroup."
killing cgroups is a process directed operation, i.e. it affects
the whole thread-group.
+ cgroup.pressure
+ A read-write single value file that allowed values are "0" and "1".
+ The default is "1".
+
+ Writing "0" to the file will disable the cgroup PSI accounting.
+ Writing "1" to the file will re-enable the cgroup PSI accounting.
+
+ This control attribute is not hierarchical, so disable or enable PSI
+ accounting in a cgroup does not affect PSI accounting in descendants
+ and doesn't need pass enablement via ancestors from root.
+
+ The reason this control attribute exists is that PSI accounts stalls for
+ each cgroup separately and aggregates it at each level of the hierarchy.
+ This may cause non-negligible overhead for some workloads when under
+ deep level of the hierarchy, in which case this control attribute can
+ be used to disable PSI accounting in the non-leaf cgroups.
+
+ irq.pressure
+ A read-write nested-keyed file.
+
+ Shows pressure stall information for IRQ/SOFTIRQ. See
+ :ref:`Documentation/accounting/psi.rst <psi>` for details.
+
Controllers
===========