tfork: add a README how to run test torture test under valgrind

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Wed Nov 28 15:57:43 CET 2018 on sn-devel-144

diff --git a/lib/util/tests/README b/lib/util/tests/README
new file mode 100644 (file)
index 0000000..c1337d5
--- /dev/null
+++ b/lib/util/tests/README
@@ -0,0 +1,22 @@
+tfork tests
+===========
+
+To run the tfork torture testsuite under valgrind with the helgrind or drd
+thread checkers, run valgrind with the --suppress option passing a suppressions
+file.
+
+For helgrind:
+
+$ valgrind \
+  --trace-children=yes \
+  --tool=helgrind \
+  --suppressions=lib/util/tests/tfork-helgrind.supp \
+  ./bin/smbtorture ncalrpc:localhost local.tfork.tfork_threads
+
+For drd:
+
+$ valgrind \
+  --trace-children=yes \
+  --tool=drd \
+  --suppressions=lib/util/tests/tfork-drd.supp \
+  ./bin/smbtorture ncalrpc:localhost local.tfork.tfork_threads