summaryrefslogtreecommitdiff
path: root/Documentation/core-api
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 16:32:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 16:32:52 -0700
commit7ab044a4f42aecba23db5ce96e763e5ec807bf42 (patch)
tree057896b2b9749e0a380e088bf4a749fb3a59b2e4 /Documentation/core-api
parent18eb3b6dff007f2e4ef4f0d8567dfb5cdb6086fc (diff)
parent18c8ae813156a6855f026de80fffb91e1a28ab3d (diff)
Merge tag 'wq-for-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo: - Concurrency-managed per-cpu work items that hog CPUs and delay the execution of other work items are now automatically detected and excluded from concurrency management. Reporting on such work items can also be enabled through a config option. - Added tools/workqueue/wq_monitor.py which improves visibility into workqueue usages and behaviors. - Arnd's minimal fix for gcc-13 enum warning on 32bit compiles, superseded by commit afa4bb778e48 in mainline. * tag 'wq-for-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Disable per-cpu CPU hog detection when wq_cpu_intensive_thresh_us is 0 workqueue: Fix WARN_ON_ONCE() triggers in worker_enter_idle() workqueue: fix enum type for gcc-13 workqueue: Track and monitor per-workqueue CPU time usage workqueue: Report work funcs that trigger automatic CPU_INTENSIVE mechanism workqueue: Automatically mark CPU-hogging work items CPU_INTENSIVE workqueue: Improve locking rule description for worker fields workqueue: Move worker_set/clr_flags() upwards workqueue: Re-order struct worker fields workqueue: Add pwq->stats[] and a monitoring script Further upgrade queue_work_on() comment
Diffstat (limited to 'Documentation/core-api')
-rw-r--r--Documentation/core-api/workqueue.rst32
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/core-api/workqueue.rst b/Documentation/core-api/workqueue.rst
index 8ec4d6270b24..a4c9b9d1905f 100644
--- a/Documentation/core-api/workqueue.rst
+++ b/Documentation/core-api/workqueue.rst
@@ -348,6 +348,37 @@ Guidelines
level of locality in wq operations and work item execution.
+Monitoring
+==========
+
+Use tools/workqueue/wq_monitor.py to monitor workqueue operations: ::
+
+ $ tools/workqueue/wq_monitor.py events
+ total infl CPUtime CPUhog CMwake mayday rescued
+ events 18545 0 6.1 0 5 - -
+ events_highpri 8 0 0.0 0 0 - -
+ events_long 3 0 0.0 0 0 - -
+ events_unbound 38306 0 0.1 - - - -
+ events_freezable 0 0 0.0 0 0 - -
+ events_power_efficient 29598 0 0.2 0 0 - -
+ events_freezable_power_ 10 0 0.0 0 0 - -
+ sock_diag_events 0 0 0.0 0 0 - -
+
+ total infl CPUtime CPUhog CMwake mayday rescued
+ events 18548 0 6.1 0 5 - -
+ events_highpri 8 0 0.0 0 0 - -
+ events_long 3 0 0.0 0 0 - -
+ events_unbound 38322 0 0.1 - - - -
+ events_freezable 0 0 0.0 0 0 - -
+ events_power_efficient 29603 0 0.2 0 0 - -
+ events_freezable_power_ 10 0 0.0 0 0 - -
+ sock_diag_events 0 0 0.0 0 0 - -
+
+ ...
+
+See the command's help message for more info.
+
+
Debugging
=========
@@ -387,6 +418,7 @@ the stack trace of the offending worker thread. ::
The work item's function should be trivially visible in the stack
trace.
+
Non-reentrance Conditions
=========================