WT-3459 Clock shifting WT test (#3555)

* WT-3459 Clock shifting WT test

* Updated for review comments

* Added description header for the script and added return codes

* enabled LONG TESTS by default as this will run in perf framework

* added check for libfaketime existence and corrected path for libfaketime

* changed libfaketime path as shell arguement

* updated the library name as well for shell arguement, and added new arguement for cpu set to be used for linux

* added usage if no arguements are given

1 files changed, 116 insertions, 0 deletions

diff --git a/test/csuite/time_shift_test.sh b/test/csuite/time_shift_test.sh
new file mode 100755
index 00000000000..ae06fd03f36
--- /dev/null
+++ b/test/csuite/time_shift_test.sh
@@ -0,0 +1,116 @@
+#! /bin/sh
+
+set -e
+
+# the purpose of this test is to ensure we use monotonic clock instead of
+# realtime clock in our code. we had the instances where WT is hanging when
+# system clock shifts (for eg: due to NTP servers). this test calculates
+# the execution time of a test(test_rwlock), shifts the clock -vely by that
+# time period and reexecutes the test. if the difference in the two execution
+# times is less than 20% test is considered passed. 20% is selected, based on
+# assumption that other factors of the environment will influence the execution
+# time by less than 20%.
+
+
+# need to enable long tests to run test_rwlock 
+export TESTUTIL_ENABLE_LONG_TESTS=1
+
+# We will run only when long tests are enabled.
+test "$TESTUTIL_ENABLE_LONG_TESTS" = "1" || exit 0
+
+EXIT_SUCCESS=0
+EXIT_FAILURE=1
+
+export DONT_FAKE_MONOTONIC=1
+RUN_OS=$(uname -s)
+
+# linux we run with cpu affinity, to control the execution time
+# if we don't control the execution time this test is not effective
+CPU_SET=0-1
+echo "test read write lock for time shifting using libfaketime"
+
+
+# check for program arguements, if not present, print usage
+if [ -z $1 ]
+then
+    echo "fail : this test needs libfaketime library with path"
+    echo "Usage :"
+    echo "       " $0 " <libpath> [cpuset] "
+    echo "         libpath : path to libfaketime library"
+    echo "         cpuset  : set of cpu's to be used for taskset on linux"
+    echo "                 : default is 0-1 "
+    exit $EXIT_FAILURE
+fi
+
+# check for the existence of dependent library
+if [ ! -r $1 ]
+then
+    echo "fail : $1 , libfaketime library is not readable"
+    exit $EXIT_FAILURE
+fi
+
+SEC1=`date +%s`
+if [ "$RUN_OS" = "Darwin" ]
+then
+    ./test_rwlock
+elif [ "$RUN_OS" = "Linux" ]
+then
+    if [ -z $2 ]
+    then
+        echo "default taskset value is 0-1"
+    else
+        CPU_SET=$2
+    fi
+    taskset -c $CPU_SET ./test_rwlock
+else
+    echo "not able to decide running OS, so exiting"
+    exit $EXIT_FAILURE
+fi
+
+SEC2=`date +%s`
+DIFF1=$((SEC2 - SEC1))
+
+# preload libfaketime
+if [ "$RUN_OS" = "Darwin" ]
+then
+    export DYLD_FORCE_FLAT_NAMESPACE=y
+    export DYLD_INSERT_LIBRARIES=$1
+    ./test_rwlock &
+else
+    LD_PRELOAD=$1 taskset -c $CPU_SET ./test_rwlock &
+fi
+
+# get pid of test run in background
+PID=$!
+
+sleep 5s
+echo "-$DIFF1""s" >| ~/.faketimerc
+
+wait $PID
+
+#kept echo statement here so as not to loose in cluster of test msgs. 
+echo "after sleeping for 5 seconds set ~/.faketimerc value as -ve $DIFF1 seconds"
+rm ~/.faketimerc
+
+if [ "$RUN_OS" = "Darwin" ]
+then
+    export DYLD_FORCE_FLAT_NAMESPACE=
+    export DYLD_INSERT_LIBRARIES=
+fi
+SEC3=`date +%s`
+DIFF2=$((SEC3 - SEC2))
+
+PERC=$((((DIFF2 - DIFF1)*100)/DIFF1)) 
+echo "execution time difference : $PERC %, less than 20% is ok"
+echo "normal execution time : $DIFF1 seconds"
+echo "fake time reduction by : $DIFF1 seconds"
+echo "execution time with -ve time shift : $DIFF2 seconds"
+
+if [ "$PERC" -le 20 ]
+then
+   echo "pass : execution time is affected $PERC % by -ve time shift"
+   exit $EXIT_SUCCESS
+else
+   echo "fail : execution time is affected $PERC % by -ve time shift"
+   exit $EXIT_FAILURE
+fi