More updates to preface.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fix false-sharing and thread-affinity problems, use pthread_setspecific().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fix uperf bug in rcutorture.h that failed to note incoming threads.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Decrease rcutorture poll() interval.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
User-level RCU performance from 128-way Power box.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fix TLS optimizations in api.h, don't nest RCU in perf tests.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Take reference to per-thread variable in rcu_nest.h to optimize.

Per-thread references are a bit expensive in pthreads, it appears.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
More data from perfsqh: after performance fixes.

Earlier data would have thread 0 always searching the array to translate
its tid to its index.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Make rcu_qs really be Classic RCU: null read-side critical sections.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add Power commands to Makefile (commented out).  Add more toy RCU data.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Move perf.perfsqh2.2008.11.29c.out to the data/ directory.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Update "toy RCU" commentary with performance numbers.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add citations describing Stephen Hawkings "two challenges" to preface.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add more toy RCU implementations.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Note counter-overflow bug that can arise given long-term preemption.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fix rcu_qs.h bug that could result in RCU failure due to counter overflow.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fix rcu_gp_ongoing() argument name ("cpu" -> "thread").

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Choose license.  Update toy-RCU section and related changes/fixes.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add data file from perfsqh2.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fixups for the reference-counting and toy-RCU sections.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>