Fix Markdown issues

[urcu.git] / README.md

diff --git a/README.md b/README.md
index 2f088fe4d6f12d58affc05eef7c7f8cc2b7da85d..f75af605db88de89e8ac6bd3d26358ff1cf5766c 100644 (file)
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ Architectures supported
 Currently, the following architectures are supported:
 
   - x86 (i386, i486, i586, i686)
-  - amd64 / x86_64
+  - amd64 / x86\_64
   - PowerPC 32/64
   - S390, S390x
   - ARM 32/64
@@ -72,6 +72,9 @@ Should also work on:
 Linux ARM depends on running a Linux kernel 2.6.15 or better, GCC 4.4 or
 better.
 
+The C compiler used needs to support at least C99. The C++ compiler used
+needs to support at least C++11.
+
 The GCC compiler versions 3.3, 3.4, 4.0, 4.1, 4.2, 4.3, 4.4 and 4.5 are
 supported, with the following exceptions:
 
@@ -91,6 +94,9 @@ supported, with the following exceptions:
 
 Clang version 3.0 (based on LLVM 3.0) is supported.
 
+Glibc >= 2.4 should work but the older version we test against is
+currently 2.17.
+
 For developers using the Git tree:
 
 This source tree is based on the autotools suite from GNU to simplify
@@ -157,8 +163,8 @@ There are multiple flavors of liburcu available:
   - `signal`,
   - `bp`.
 
-The API members start with the prefix "urcu_<flavor>_", where
-<flavor> is the chosen flavor name.
+The API members start with the prefix `urcu_<flavor>_`, where
+`<flavor>` is the chosen flavor name.
 
 
 ### Usage of `liburcu-memb`
@@ -379,8 +385,8 @@ For always-on debugging self-checks:
        ./configure --enable-rcu-debug
 
 For fine grained enabling of debugging self-checks, build
-userspace-rcu with DEBUG_RCU defined and compile dependent
-applications with DEBUG_RCU defined when necessary.
+userspace-rcu with `DEBUG_RCU` defined and compile dependent
+applications with `DEBUG_RCU` defined when necessary.
 
 Warning: Enabling this feature result in a performance penalty.
 
@@ -420,14 +426,42 @@ Make targets
 ------------
 
 In addition to the usual `make check` target, Userspace RCU features
-`make regtest` and `make bench` targets:
+`make regtest`, `make short_bench` and `make long_bench` targets:
 
   - `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.
+  - `make short_bench`: short benchmarks, 3 seconds per test.
+  - `make long_bench`: long (many hours) benchmarks, 30 seconds per test.
+
+
+Known issues
+------------
+
+There is an application vs library compatibility issue between
+applications built using Userspace RCU 0.10 headers linked against
+Userspace RCU 0.11 or 0.12 shared objects. The problem occurs as
+follows:
+
+  - An application executable is built with `_LGPL_SOURCE` defined, includes
+    any of the Userspace RCU 0.10 urcu flavor headers, and is built
+    without the -fpic compiler option.
+
+  - The Userspace RCU 0.10 library shared objects are updated to 0.11
+    or 0.12 without rebuilding the application.
+
+  - The application will hang, typically when RCU grace period
+    (synchronize_rcu) is invoked.
+
+Some possible work-arounds for this are:
+
+  - Rebuild the application against Userspace RCU 0.11+.
+
+  - Rebuild the application with -fpic.
+
+  - Upgrade Userspace RCU to 0.13+ without installing 0.11 nor 0.12.
 
 
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