[cfe-commits] r170311 - /cfe/trunk/docs/ThreadSanitizer.rst
Dmitry Vyukov
dvyukov at google.com
Sun Dec 16 23:16:55 PST 2012
Author: dvyukov
Date: Mon Dec 17 01:16:54 2012
New Revision: 170311
URL: http://llvm.org/viewvc/llvm-project?rev=170311&view=rev
Log:
tsan: update docs
Modified:
cfe/trunk/docs/ThreadSanitizer.rst
Modified: cfe/trunk/docs/ThreadSanitizer.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/ThreadSanitizer.rst?rev=170311&r1=170310&r2=170311&view=diff
==============================================================================
--- cfe/trunk/docs/ThreadSanitizer.rst (original)
+++ cfe/trunk/docs/ThreadSanitizer.rst Mon Dec 17 01:16:54 2012
@@ -6,7 +6,8 @@
ThreadSanitizer is a tool that detects data races. It consists of a compiler
instrumentation module and a run-time library. Typical slowdown introduced by
-ThreadSanitizer is **5x-15x** (TODO: these numbers are approximate so far).
+ThreadSanitizer is about **5x-15x**. Typical memory overhead introduced by
+ThreadSanitizer is about **5x-10x**.
How to build
------------
@@ -17,8 +18,8 @@
Supported Platforms
-------------------
-ThreadSanitizer is supported on Linux x86_64 (tested on Ubuntu 10.04). Support
-for MacOS 10.7 (64-bit only) is planned for late 2012. Support for 32-bit
+ThreadSanitizer is supported on Linux x86_64 (tested on Ubuntu 10.04 and 12.04).
+Support for MacOS 10.7 (64-bit only) is planned for 2013. Support for 32-bit
platforms is problematic and not yet planned.
Usage
@@ -32,7 +33,7 @@
.. code-block:: c++
- % cat projects/compiler-rt/lib/tsan/output_tests/tiny_race.c
+ % cat projects/compiler-rt/lib/tsan/lit_tests/tiny_race.c
#include <pthread.h>
int Global;
void *Thread1(void *x) {
@@ -55,36 +56,37 @@
.. code-block:: bash
- % TSAN_OPTIONS=strip_path_prefix=`pwd`/ # Don't print full paths.
- % ./a.out 2> log
- % cat log
+ % ./a.out
WARNING: ThreadSanitizer: data race (pid=19219)
- Write of size 4 at 0x7fcf47b21bc0 by thread 1:
+ Write of size 4 at 0x7fcf47b21bc0 by thread T1:
#0 Thread1 tiny_race.c:4 (exe+0x00000000a360)
+
Previous write of size 4 at 0x7fcf47b21bc0 by main thread:
#0 main tiny_race.c:10 (exe+0x00000000a3b4)
- Thread 1 (running) created at:
- #0 pthread_create ??:0 (exe+0x00000000c790)
+
+ Thread T1 (running) created at:
+ #0 pthread_create tsan_interceptors.cc:705 (exe+0x00000000c790)
#1 main tiny_race.c:9 (exe+0x00000000a3a4)
Limitations
-----------
* ThreadSanitizer uses more real memory than a native run. At the default
- settings the memory overhead is 9x plus 9Mb per each thread. Settings with 5x
- and 3x overhead (but less accurate analysis) are also available.
+ settings the memory overhead is 5x plus 1Mb per each thread. Settings with 3x
+ (less accurate analysis) and 9x (more accurate analysis) overhead are also
+ available.
* ThreadSanitizer maps (but does not reserve) a lot of virtual address space.
This means that tools like ``ulimit`` may not work as usually expected.
-* Static linking is not supported.
-* ThreadSanitizer requires ``-fPIE -pie``.
+* Libc/libstdc++ static linking is not supported.
+* ThreadSanitizer requires ``-fPIE -pie`` compiler flags.
Current Status
--------------
-ThreadSanitizer is in alpha stage. It is known to work on large C++ programs
-using pthreads, but we do not promise anything (yet). C++11 threading is not
-yet supported. The test suite is integrated into CMake build and can be run
-with ``make check-tsan`` command.
+ThreadSanitizer is in beta stage. It is known to work on large C++ programs
+using pthreads, but we do not promise anything (yet). C++11 threading is
+supported with llvm libstdc++. The test suite is integrated into CMake build
+and can be run with ``make check-tsan`` command.
We are actively working on enhancing the tool --- stay tuned. Any help,
especially in the form of minimized standalone tests is more than welcome.
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