Add hints to README file.

Author: nascheme

README.md

@@ -1 +1,64 @@
-Build container images for CPython, numpy, etc with sanitizer options enbled.
+Build container images for CPython, numpy, etc with sanitizer options enabled.
+
+Available container images
+--------------------------
+
+Free-threaded Python builds with TSAN enabled:
+
+    ghcr.io/nascheme/cpython-tsan:3.13t
+    ghcr.io/nascheme/cpython-tsan:3.14t
+
+Above builds with "numpy" compiled with TSAN as well:
+
+    ghcr.io/nascheme/numpy-tsan:3.13t
+    ghcr.io/nascheme/numpy-tsan:3.14t
+
+Above builds with "scipy" compiled with TSAN as well:
+
+    ghcr.io/nascheme/scipy-tsan:3.13t
+    ghcr.io/nascheme/scipy-tsan:3.14t
+
+
+Hints
+-----
+
+To open a command prompt inside the container, you can use the following
+command:
+
+    docker run -it --rm <image url> bash
+
+If you want to open additional command prompts, you can use "exec", e.g.
+
+    docker exec -it <container ID> bash
+
+The container ID is shown in the prompt as `root@<container ID>`.  If you want
+changes you make inside the container to persist, you should remove the `--rm`
+command line argument.  Note that you will need to remember to manually remove
+the container after you are finished with it.
+
+Python is installed under `/work/.pyenv/versions`.  The `python` command
+will already be in the path.
+
+Depending on the version of Linux running on the container host, you may need
+to adjust some settings.  To avoid ASLR interferring with the TSAN checking,
+the following config change may be required:
+
+    sudo sysctl vm.mmap_rnd_bits=28
+
+Since this change reduces security, you likely want to revert to the default
+number of bits after running tests.
+
+If you need to install packages using "apt", the list of packages needs
+to be updated first, e.g.
+
+    apt-get update && apt-get install <pkg name>
+
+
+Running scipy tests
+-------------------
+
+Example of running a single test with pytest:
+
+    cd /work/.pyenv/versions/3.13.2t/lib/python3.13t/site-packages/scipy
+    PYTHON_GIL=0 TSAN_OPTIONS=allocator_may_return_null=1:halt_on_error=1 \
+        pytest -v -s optimize/tests/test_minpack.py::TestFSolve::test_concurrent_no_gradient