Commit Graph

5 Commits

Author SHA1 Message Date
Paul E. McKenney c25197841e 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>
2015-02-26 11:57:29 -08:00
Paul E. McKenney 8bdf7a252b nohz_full: Add testing information to documentation
This commit adds information about testing nohz_full, and also emphasizes
the fact that you need a multi-CPU system to get any benefit from nohz_full.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-08-18 18:06:55 -07:00
Paul E. McKenney ce5f4fc861 nohz_full: Document additional restrictions
This commit calls out the potential for slowing the tick even when there
are multiple runnable processes per CPU,  It also points out that current
mainlined version keeps the tick going on at least one CPU even when all
CPUs are otherwise idle.  Finally, it notes the need for a 1-HZ tick in
order to calculate CPU load, maintain sched average, compute CFS entity
vruntime, compute avenrun, and carry out load balancing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-06-10 13:42:38 -07:00
Paul E. McKenney 295fde89be nohz_full: Update based on Sedat Dilek review
Make it more clear that there are three options, and give hints as
to which of the three is most likely to be useful in different
situations.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-06-10 13:42:37 -07:00
Paul E. McKenney 0c87f9b5ca nohz_full: Add documentation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Olivier Baetz <olivier.baetz@novasparks.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
2013-04-27 16:41:43 -07:00