| Last updated February 17, 2008 |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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| Data-race detection algorithm |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| - Implement segment merging, such that the number of segments per thread |
| remains limited even when there is no synchronization between threads. |
| - Add locking order checking. |
| - Discuss on the Valgrind mailing list how to make it possible to call |
| POSIX thread synchronization primitives from client code (drd_intercepts.c) |
| without triggering Valgrind's redirection mechanism. |
| - Make sure -v works again with exp-drd. |
| - Continue the discussion on the Valgrind mailing list about docbook and |
| 'make dist'. |
| - Continue the discussion on the Valgrind mailing list about -Wformat. |
| - Enable format string checking for DRD during compilation. |
| - Propose to modify tl_assert() / vg_assert() such that it uses |
| __builtin_expect. |
| - Explain on the Valgrind mailing list the difference between a bus lock |
| and acquire / release labels. |
| - Add configure tests for the name of the 'kind' member in pthread_mutex_t. |
| - Find out why a race is reported on std::string::string(std::string const&) |
| (stc test case 16). |
| - Find out why no races are reported on matinv_openmp.c when "private(k)" is |
| removed. |
| - Add support for objects that are shared over threads and that use reference |
| counting, e.g. std::string -- no races should be reported on the reference |
| count. |
| - Add test programs for destroying a condition variable / semaphore / barrier |
| being waited upon. |
| - Make sure an error message is printed if no debug information is found in |
| libopenmp.so.1. |
| - Make sure tc14_laog_dinphils is run during exp-drd regression tests. |
| - Find out why no line number or variable name information is printed for |
| races detected in parallel sections of OpenMP programs. An example: |
| ./vg-in-place --tool=exp-drd exp-drd/tests/omp_prime 4 -t 2 |
| - Find out why there are races reported on exp-drd/tests/pth_detached_sem |
| on AMD64 (information about freeing stack memory not passed to DRD ?): |
| ./vg-in-place --tool=exp-drd exp-drd/tests/pth_detached_sem 3 0 |
| - Find a way for suppressing races reported on _IO_2_1_stdout. This race is |
| triggered by calling printf() from more than one thread. Examples (AMD64): |
| ./vg-in-place --tool=exp-drd exp-drd/tests/tc21_pthonce |
| ./vg-in-place --tool=exp-drd exp-drd/tests/pth_detached 10 10 1 |
| - Find out why 'matinv 400' runs faster in 32-bit mode than in 64-bit mode |
| on the same CPU. |
| - testing on PPC and AIX (current implementation is only tested on X86 and |
| AMD64). |
| - Convert the array in drd_thread.c with thread information into an OSet. |
| - Performance testing and tuning. |
| - Optimize run time of the following test case: |
| ./vg-in-place --tool=exp-drd exp-drd/tests/matinv 100 |
| |
| Testing |
| ~~~~~~~ |
| - testing with more complex multithreaded test programs. |
| - test exp-drd's performance with the SPLASH-2 software, e.g. fft |
| (http://www-flash.stanford.edu/apps/SPLASH/) or the PARSEC benchmark |
| (http://parsec.cs.princeton.edu/license.htm). |
| - test with Synfig Studio (see also http://bugs.kde.org/show_bug.cgi?id=158555) |
| |
| |
| Documentation |
| ~~~~~~~~~~~~~ |
| - Document the command-line options of the exp-drd tool. |
| - Explain that happens-before race detectors are also suited for certain |
| classes of programs that do not follow a locking discipline |
| (e.g. exp-drd/test/matinv.c). |
| |
| |
| Limitations |
| ~~~~~~~~~~~ |
| - Does not work with a glibc library compiled with linuxthreads -- NPTL is |
| required for proper operation. |
| |
| |
| Known bugs |
| ~~~~~~~~~~ |
| - Gets killed by the OOM handler for realistically sized applications, |
| e.g. knode and OpenOffice. |
| - [x86_64] Reports "Allocation context: unknown" for BSS symbols on AMD64 |
| (works fine on i386). This is a bug in Valgrind's debug info reader |
| -- VG_(find_seginfo)() returns NULL for BSS symbols on x86_64. Not yet in |
| the KDE bug tracking system. |