* CFLAGS="-m64 -g -O2" ./configure
Forcing a 32-bit build with 386 backward compatibility:
- * CFLAGS="-m32 -g -O2" ./configure --target=i386-pc-linux-gnu
+ * CFLAGS="-m32 -g -O2" ./configure --host=i386-pc-linux-gnu
Forcing a 32-bit build for Sparcv9 (typical for Sparc v9)
* CFLAGS="-m32 -Wa,-Av9a -g -O2" ./configure
-----------------------
Currently, Linux x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64,
-S390, S390x, ARM, Alpha, ia64 and Sparcv9 32/64 are supported. Tested on
-Linux, FreeBSD 8.2/9.0, and Cygwin. Should also work on: Android, NetBSD 5,
-OpenBSD, Darwin (more testing needed before claiming support for these OS).
+S390, S390x, ARM, MIPS, Alpha, ia64 and Sparcv9 32/64 are supported.
+Tested on Linux, FreeBSD 8.2/8.3/9.0/9.1/10.0 i386/amd64, and Cygwin.
+Should also work on: Android, NetBSD 5, OpenBSD, Darwin (more testing
+needed before claiming support for these OS).
Linux ARM depends on running a Linux kernel 2.6.15 or better, GCC 4.4 or
better.
support. For ARM this was introduced with gcc 4.4:
http://gcc.gnu.org/gcc-4.4/changes.html
+Clang version 3.0 (based on LLVM 3.0) is supported.
+
+Building on MacOS X (Darwin) requires a work-around for processor
+detection:
+ # 32-bit
+ ./configure --build=i686-apple-darwin11
+ # 64-bit
+ ./configure --build=x86_64-apple-darwin11
+
For developers using the git tree:
This source tree is based on the autotools suite from GNU to simplify
See the relevant API documentation files in doc/. The APIs provided by
Userspace RCU are, by prefix:
-- rcu_ : Read-Copy Update
+- rcu_ : Read-Copy Update (see doc/rcu-api.txt)
- cmm_ : Concurrent Memory Model
- caa_ : Concurrent Architecture Abstraction
-- cds_ : Concurrent Data Structures
-- uatomic_: Userspace Atomic
+- cds_ : Concurrent Data Structures (see doc/cds-api.txt)
+- uatomic_: Userspace Atomic (see doc/uatomic-api.txt)
QUICK START GUIDE
instead of inlines, so your application can link with the library.
* Linking with one of the libraries below is always necessary even for
LGPL and GPL applications.
+ * Define URCU_INLINE_SMALL_FUNCTIONS before including Userspace RCU
+ headers if you want Userspace RCU to inline small functions (10
+ lines or less) into the application. It can be used by applications
+ distributed under any kind of license, and does *not* make the
+ application a derived work of Userspace RCU.
+
+ Those small inlined functions are guaranteed to match the library
+ content as long as the library major version is unchanged.
+ Therefore, the application *must* be compiled with headers matching
+ the library major version number. Applications using
+ URCU_INLINE_SMALL_FUNCTIONS may be unable to use debugging
+ features of Userspace RCU without being recompiled.
+
Usage of liburcu
should only be taken when the RCU reader thread is "offline"
(this can be performed by calling rcu_thread_offline()).
+Interaction with fork()
+
+ Special care must be taken for applications performing fork() without
+ any following exec(). This is caused by the fact that Linux only clones
+ the thread calling fork(), and thus never replicates any of the other
+ parent thread into the child process. Most liburcu implementations
+ require that all registrations (as reader, defer_rcu and call_rcu
+ threads) should be released before a fork() is performed, except for the
+ rather common scenario where fork() is immediately followed by exec() in
+ the child process. The only implementation not subject to that rule is
+ liburcu-bp, which is designed to handle fork() by calling
+ rcu_bp_before_fork, rcu_bp_after_fork_parent and
+ rcu_bp_after_fork_child.
+
+ Applications that use call_rcu() and that fork() without
+ doing an immediate exec() must take special action. The parent
+ must invoke call_rcu_before_fork() before the fork() and
+ call_rcu_after_fork_parent() after the fork(). The child
+ process must invoke call_rcu_after_fork_child().
+ Even though these three APIs are suitable for passing to
+ pthread_atfork(), use of pthread_atfork() is *STRONGLY
+ DISCOURAGED* for programs calling the glibc memory allocator
+ (malloc(), calloc(), free(), ...) within call_rcu callbacks.
+ This is due to limitations in the way glibc memory allocator
+ handles calls to the memory allocator from concurrent threads
+ while the pthread_atfork() handlers are executing.
+ Combining e.g.:
+ * call to free() from callbacks executed within call_rcu worker
+ threads,
+ * executing call_rcu atfork handlers within the glibc pthread
+ atfork mechanism,
+ will sometimes trigger interesting process hangs. This usually
+ hangs on a memory allocator lock within glibc.
+
+Thread Local Storage (TLS)
+
+ Userspace RCU can fall back on pthread_getspecific() to emulate
+ TLS variables on systems where it is not available. This behavior
+ can be forced by specifying --disable-compiler-tls as configure
+ argument.
+
Usage of DEBUG_RCU
DEBUG_RCU is used to add internal debugging self-checks to the
theoretically yielding slightly better performance.
-Interaction with fork()
+MAKE TARGETS
+------------
- Special care must be taken for applications performing fork() without
- any following exec(). This is caused by the fact that Linux only clones
- the thread calling fork(), and thus never replicates any of the other
- parent thread into the child process. Most liburcu implementations
- require that all registrations (as reader, defer_rcu and call_rcu
- threads) should be released before a fork() is performed, except for the
- rather common scenario where fork() is immediately followed by exec() in
- the child process. The only implementation not subject to that rule is
- liburcu-bp, which is designed to handle fork() by calling
- rcu_bp_before_fork, rcu_bp_after_fork_parent and
- rcu_bp_after_fork_child.
+In addition to the usual "make check" target, Userspace RCU features
+"make regtest" and "make bench" targets.
- Applications that use call_rcu() and that fork() without
- doing an immediate exec() must take special action. The parent
- must invoke call_rcu_before_fork() before the fork() and
- call_rcu_after_fork_parent() after the fork(). The child
- process must invoke call_rcu_after_fork_child().
- These three APIs are suitable for passing to pthread_atfork().
+make check: Short tests, meant to be run when rebuilding or porting
+ Userspace RCU.
+
+make regtest: Long (many hours) test, meant to be run when modifying
+ Userspace RCU or porting it to a new architecture or
+ operating system.
+
+make bench: Long (many hours) benchmarks.
+
+CONTACTS
+--------
+
+You can contact the maintainers on the following mailing list:
+lttng-dev@lists.lttng.org
projects / urcu.git / blobdiff