Restrict supported arch ot P6+ on Intel x86 32.

[urcu.git] / README

diff --git a/README b/README
index 966006613215c8d1ee1415dcca6de46860edb84c..f9437dba2857856b726cc4539b6deeafaf09f668 100644 (file)
--- a/README
+++ b/README
@@ -4,9 +4,25 @@ by Mathieu Desnoyers and Paul E. McKenney
 BUILDING
 --------
 
+       ./bootstrap (skip if using tarball)
+       ./configure
        make
        make install
-       
+
+       Note:   Forcing 32-bit build:
+               * CFLAGS=-m32 ./configure
+
+               Forcing 64-bit build:
+               * CFLAGS=-m64 ./configure
+
+ARCHITECTURES SUPPORTED
+-----------------------
+
+Currently, x86 (only P6+), x86 64, PowerPC 32/64 and S390 are
+supported. The current use of sys_futex() makes it Linux-dependent, although
+this portability limitation might go away in a near future by using the pthread
+cond vars. Also, the restriction against i386, i486 and Pentium might go away if
+we integrate some of glibc runtime CPU-detection tests.
 
 QUICK START GUIDE
 -----------------
@@ -31,7 +47,7 @@ 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
@@ -48,6 +64,17 @@ 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
@@ -68,6 +95,15 @@ 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 call_rcu() primitive to enqueue delayed callbacks. Queued
+         callbacks are executed in batch periodically after a grace period.
+         Do _not_ use call_rcu() within a read-side critical section, because
+         it may call synchronize_rcu() if the thread queue is full.
+
 Being careful with signals
 
        The liburcu library uses signals internally. The signal handler is