linux/Documentation/RCU
Paul E. McKenney 269dcc1c2e rcu: Add tracing data to support queueing models
The current tracing data is not sufficient to deduce the average time
that a callback spends waiting for a grace period to end.  Add three
per-CPU counters recording the number of callbacks invoked (ci), the
number of callbacks orphaned (co), and the number of callbacks adopted
(ca).  Given the existing callback queue length (ql), the average wait
time in absence of CPU hotplug operations is ql/ci.  The units of wait
time will be in terms of the duration over which ci was measured.

In the presence of CPU hotplug operations, there is room for argument,
but ql/(ci-co+ca) won't steer you too far wrong.

Also fixes a typo called out by Lucas De Marchi <lucas.de.marchi@gmail.com>.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-09-23 09:16:53 -07:00
..
00-INDEX
arrayRCU.txt
checklist.txt rcu: document ways of stalling updates in low-memory situations 2010-08-20 09:00:14 -07:00
listRCU.txt
lockdep.txt
NMI-RCU.txt
rcu.txt
rcubarrier.txt
rculist_nulls.txt
rcuref.txt
RTFP.txt
stallwarn.txt rcu: upgrade stallwarn.txt documentation for CPU-bound RT processes 2010-08-23 16:34:02 -07:00
torture.txt
trace.txt rcu: Add tracing data to support queueing models 2010-09-23 09:16:53 -07:00
UP.txt
whatisRCU.txt