rcu-tasks: Provide boot parameter to delay IPIs until late in grace period

Browse source

This commit provides a rcupdate.rcu_task_ipi_delay kernel boot parameter
that specifies how old the RCU tasks trace grace period must be before
the grace-period kthread starts sending IPIs.  This delay allows more
tasks to pass through rcu_tasks_qs() quiescent states, thus reducing
(or even eliminating) the number of IPIs that must be sent.

On a short rcutorture test setting this kernel boot parameter to HZ/2
resulted in zero IPIs for all 877 RCU-tasks trace grace periods that
elapsed during that test.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

...

This commit is contained in:

Paul E. McKenney 2020-03-17 11:39:26 -07:00

parent 88092d0c99

commit b0afa0f056

2 changed files with 16 additions and 4 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

7

Documentation/admin-guide/kernel-parameters.txt

View file

13

kernel/rcu/tasks.h

View file