-build instructions for userspace-rcu library :
+Userspace RCU Implementatation
+by Mathieu Desnoyers and Paul E. McKenney
-make pthreads-x86
-or
-make pthreads-ppc
+BUILDING
+--------
-make
-make install
+ make
+ make install
+
-Usage :
+QUICK START GUIDE
+-----------------
-Registration of _each thread_ calling read-side critical sections must be done
-with rcu_register_thread() before using rcu_read_lock()/rcu_read_unlock().
+Initialization
-Unregistration should be performed with rcu_unregister_thread() before exiting
-the thread.
+ Each thread that has reader critical sections (that uses
+ rcu_read_lock()/rcu_read_unlock() must first register to the URCU
+ library. This is done by calling rcu_register_thread().
- Mathieu Desnoyers
+Reading
+
+ Reader critical sections must be protected by locating them between
+ calls to rcu_read_lock() and rcu_read_unlock(). Inside that lock,
+ rcu_dereference() may be called to read an RCU protected pointer.
+
+Writing
+
+ rcu_assign_pointer() and rcu_xchg_pointer() may be called anywhere.
+ After, synchronize_rcu() must be called. When it returns, the old
+ values are not in usage anymore.
+
+Being careful with signals
+
+ The library uses signals internally. The signal handler is
+ registered with the SA_RESTART flag. However, these signals may cause
+ some non-restartable system calls to fail with errno = EINTR. Care
+ should be taken to restart system calls manually if they fail with this
+ error. A list of non-restartable system calls may be found in
+ signal(7). To ensure the Userspace RCU library does not use signals,
+ define CONFIG_URCU_AVOID_SIGNALS at compile-time.
+
+ Read-side critical sections can sit in a signal handler. Be careful,
+ however, to disable these signals between thread creation and calls to
+ rcu_register_thread(), because a signal handler nesting on an
+ unregistered thread would not be allowed to call rcu_read_lock().
+
+Usage of CONFIG_URCU_AVOID_SIGNALS
+
+ CONFIG_URCU_AVOID_SIGNALS uses full SMP barriers for readers. This
+ eliminates the need for signals but results in slower reads.
+
+Usage of DEBUG_RCU
+
+ DEBUG_RCU is used to add internal debugging self-checks to the
+ RCU library. This define adds a performance penality when enabled.
+ Can be enabled by uncommenting the corresponding line in
+ Makefile.build.inc.
+
+Usage of DEBUG_YIELD
+
+ DEBUG_YIELD is used to add random delays in the code for testing
+ purposes.