fixes in ceph tests, add linearity plot
diff --git a/wally/suits/io/ceph.cfg b/wally/suits/io/ceph.cfg
index 9e98dd6..c9b2f53 100644
--- a/wally/suits/io/ceph.cfg
+++ b/wally/suits/io/ceph.cfg
@@ -12,8 +12,8 @@
 NUMJOBS_SHORT={% 1, 5, 10 %}
 
 size=30G
-ramp_time=30
-runtime=60
+ramp_time=5
+runtime=30
 
 # ---------------------------------------------------------------------
 # check different thread count, sync mode. (latency, iops) = func(th_count)