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 rcu: Documentation update for CONFIG_PROVE_RCU 2010-02-25 10:34:53 +01:00
arrayRCU.txt
checklist.txt rcu: document ways of stalling updates in low-memory situations 2010-08-20 09:00:14 -07:00
listRCU.txt Doc: Fix wrong API example usage of call_rcu(). 2009-04-02 01:33:50 -07:00
lockdep.txt rcu: Update docs for rcu_access_pointer and rcu_dereference_protected 2010-04-14 12:20:12 +02:00
NMI-RCU.txt rcu: Update docs for rcu_access_pointer and rcu_dereference_protected 2010-04-14 12:20:12 +02:00
rcu.txt rcu: 1Q2010 update for RCU documentation 2010-01-16 10:25:22 +01:00
rcubarrier.txt rcu: Add synchronize_sched_expedited() rcutorture doc + updates 2009-07-03 10:02:29 +02:00
rculist_nulls.txt netfilter: nf_conntrack: nf_conntrack_alloc() fixes 2009-07-16 14:03:40 +02:00
rcuref.txt doc/RCU: fix pseudocode in rcuref.txt 2008-09-10 08:36:07 +02:00
RTFP.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
stallwarn.txt rcu: upgrade stallwarn.txt documentation for CPU-bound RT processes 2010-08-23 16:34:02 -07:00
torture.txt sched: replace migration_thread with cpu_stop 2010-05-06 18:49:21 +02:00
trace.txt rcu: Add tracing data to support queueing models 2010-09-23 09:16:53 -07:00
UP.txt rcu: Add synchronize_sched_expedited() rcutorture doc + updates 2009-07-03 10:02:29 +02:00
whatisRCU.txt rcu: Update docs for rcu_access_pointer and rcu_dereference_protected 2010-04-14 12:20:12 +02:00