X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=README;h=af0a9c2d3d50b13c8057f4eb65aeb7df8bea74bb;hb=1ed9b67726a52a0f4189cc1b58ca0141f7b1614f;hp=7753c8f957dfbf6acd9244b2fa2d9759879bc3f3;hpb=0a1d290b4432036a7c1bf4a1b251ec9086036a87;p=urcu.git

diff --git a/README b/README
index 7753c8f..af0a9c2 100644
--- a/README
+++ b/README
@@ -4,9 +4,26 @@ by Mathieu Desnoyers and Paul E. McKenney
 BUILDING
 --------
 
+	./bootstrap (skip if using tarball)
+	./configure
 	make
 	make install
-	
+
+	Hints:	Forcing 32-bit build:
+		* CFLAGS="-m32 -g -O2" ./configure
+
+		Forcing 64-bit build:
+		* CFLAGS="-m64 -g -O2" ./configure
+
+		Forcing a 32-bit build with 386 backward compatibility:
+		* CFLAGS="-m32 -g -O2" ./configure --target=i386-pc-linux-gnu
+
+ARCHITECTURES SUPPORTED
+-----------------------
+
+Currently, x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64, S390, S390x
+and Sparc64 are supported. Only tested on Linux so far, but should
+theoretically work on other operating systems.
 
 QUICK START GUIDE
 -----------------
@@ -31,7 +48,7 @@ Usage of liburcu
 Usage of liburcu-mb
 
 	* #include <urcu.h>
-	* Compile code with "-DURCU_MB"
+	* Compile any _LGPL_SOURCE code using this library with "-DURCU_MB".
 	* Link with "-lurcu-mb".
 	* This version of the urcu library does not need to
 	  reserve a signal number. URCU_MB uses full memory barriers for
@@ -48,11 +65,24 @@ Usage of liburcu-qsbr
 	  the threads are not active. It provides the fastest read-side at the
 	  expense of more intrusiveness in the application code.
 
+Usage of liburcu-bp
+
+	* #include <urcu-bp.h>
+	* Link with "-lurcu-bp".
+	* The BP library flavor stands for "bulletproof". It is specifically
+	  designed to help tracing library to hook on applications without
+	  requiring to modify these applications. urcu_init(),
+	  rcu_register_thread() and rcu_unregister_thread() all become nops.
+	  The state is dealt with by the library internally at the expense of
+	  read-side and write-side performance.
+
 Initialization
 
 	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().
+	library. This is done by calling rcu_register_thread(). Unregistration
+	must be performed before exiting the thread by using
+	rcu_unregister_thread().
 
 Reading
 
@@ -66,6 +96,23 @@ Writing
 	After, synchronize_rcu() must be called. When it returns, the old
 	values are not in usage anymore.
 
+Usage of liburcu-defer
+
+	* #include <urcu-defer.h>
+	* Link with "-lurcu-defer"
+	* Provides defer_rcu() primitive to enqueue delayed callbacks. Queued
+	  callbacks are executed in batch periodically after a grace period.
+	  Do _not_ use defer_rcu() within a read-side critical section, because
+	  it may call synchronize_rcu() if the thread queue is full.
+	* Provides defer_rcu_ratelimit() primitive, which acts just like
+	  defer_rcu(), but takes an additional rate limiter callback forcing
+	  synchronized callback execution of the limiter returns non-zero.
+	* Requires that rcu_defer_barrier() must be called in library destructor
+	  if a library queues callbacks and is expected to be unloaded with
+	  dlclose().
+	* Its API is currently experimental. It may change in future library
+	  releases.
+
 Being careful with signals
 
 	The liburcu library uses signals internally. The signal handler is
@@ -98,3 +145,13 @@ Usage of DEBUG_YIELD
 
 	DEBUG_YIELD is used to add random delays in the code for testing
 	purposes.
+
+SMP support
+
+	By default the library is configured to use synchronization primitives
+	adequate for SMP systems. On uniprocessor systems, support for SMP
+	systems can be disabled with:
+
+		./configure --disable-smp-support
+
+	theoretically yielding slightly better performance.