Add 'null' perf test

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/examples/null b/examples/null
new file mode 100644
index 0000000..9d2f3e0
--- /dev/null
+++ b/examples/null
@@ -0,0 +1,10 @@
+[global]
+bs=4k
+gtod_reduce=1
+
+[null]
+ioengine=null
+size=100g
+rw=randread
+norandommap
+time_based=0