X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=README.md;h=1e755894d9cb811e26a155774cc68607c850fce5;hb=fada682f0d6e680f18e3243aa0af607dfafcbd32;hp=2f088fe4d6f12d58affc05eef7c7f8cc2b7da85d;hpb=0af4b40c1b5d70e25321181f5c437982b132d034;p=urcu.git

diff --git a/README.md b/README.md
index 2f088fe..1e75589 100644
--- a/README.md
+++ b/README.md
@@ -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
@@ -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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