Merge pull request ceph#5900 from ritz303/wip-doc-12899

doc: Updated the rados command man page to include the --run-name opt…

Reviewed-by: Kefu Chai <[email protected]>

doc/man/8/rados.rst

@@ -116,7 +116,9 @@ Pool specific commands
   sequential or random. Before running one of the reading benchmarks,
   run a write benchmark with the *--no-cleanup* option. The default
   object size is 4 MB, and the default number of simulated threads
-  (parallel writes) is 16.
+  (parallel writes) is 16. The *--run-name <label>* option is useful
+  for benchmarking a workload test from multiple clients. The *<label>*
+  is an arbitrary object name.
   Note: -b *objsize* option is valid only in *write* mode.
 
 :command:`cleanup`