torture: Use elapsed time to detect hangs

The kvm-test-1-run.sh currently counts "sleep 1" commands to detect
hangs.  This can fail spectacularly on busy systems, where "sleep 1"
might take far longer than one second to complete.  This commit
therefore changes hang detection to use elapsed time measurements.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index 2bfdb48..27e544e 100755 (executable)
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -167,14 +167,18 @@ fi
 qemu_pid=$!
 commandcompleted=0
 echo Monitoring qemu job at pid $qemu_pid
-for ((i=0;i<$seconds;i++))
+while :
 do
+       kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
        if kill -0 $qemu_pid > /dev/null 2>&1
        then
+               if test $kruntime -ge $seconds
+               then
+                       break;
+               fi
                sleep 1
        else
                commandcompleted=1
-               kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
                if test $kruntime -lt $seconds
                then
                        echo Completed in $kruntime vs. $seconds >> $resdir/Warnings 2>&1
@@ -194,20 +198,22 @@ done
 if test $commandcompleted -eq 0
 then
        echo Grace period for qemu job at pid $qemu_pid
-       for ((i=0;i<=$grace;i++))
+       while :
        do
+               kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
                if kill -0 $qemu_pid > /dev/null 2>&1
                then
-                       sleep 1
+                       :
                else
                        break
                fi
-               if test $i -eq $grace
+               if test $kruntime -ge $((seconds + grace))
                then
-                       kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }'`
                        echo "!!! Hang at $kruntime vs. $seconds seconds" >> $resdir/Warnings 2>&1
                        kill -KILL $qemu_pid
+                       break
                fi
+               sleep 1
        done
 fi