documentation: Update NO_HZ_FULL interaction with POSIX timers
POSIX timers are no longer starved on adaptive-ticks CPUs. Instead, they
prevent affected CPUs from entering adaptive-ticks mode. This commit
therefore updates the NO_HZ.txt documentation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/Documentation/timers/NO_HZ.txt b/Documentation/timers/NO_HZ.txt
index cca122f..6eaf576 100644
--- a/Documentation/timers/NO_HZ.txt
+++ b/Documentation/timers/NO_HZ.txt
@@ -158,13 +158,9 @@
to the need to inform kernel subsystems (such as RCU) about
the change in mode.
-3. POSIX CPU timers on adaptive-tick CPUs may miss their deadlines
- (perhaps indefinitely) because they currently rely on
- scheduling-tick interrupts. This will likely be fixed in
- one of two ways: (1) Prevent CPUs with POSIX CPU timers from
- entering adaptive-tick mode, or (2) Use hrtimers or other
- adaptive-ticks-immune mechanism to cause the POSIX CPU timer to
- fire properly.
+3. POSIX CPU timers prevent CPUs from entering adaptive-tick mode.
+ Real-time applications needing to take actions based on CPU time
+ consumption need to use other means of doing so.
4. If there are more perf events pending than the hardware can
accommodate, they are normally round-robined so as to collect