diff --git a/src/mon/MonCommands.h b/src/mon/MonCommands.h
index 627546b4f05..10c0e01e920 100644
--- a/src/mon/MonCommands.h
+++ b/src/mon/MonCommands.h
@@ -352,6 +352,9 @@ COMMAND("osd perf", \
         "osd", \
         "r", \
         "cli,rest")
+COMMAND("osd blocked-by", \
+	"print histogram of which OSDs are blocking their peers", \
+	"osd", "r", "cli,rest")
 COMMAND("osd getmaxosd", "show largest OSD id", "osd", "r", "cli,rest")
 COMMAND("osd find " \
 	"name=id,type=CephInt,range=0", \
diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc
index 6047cb15c43..8f0d437bd36 100644
--- a/src/mon/OSDMonitor.cc
+++ b/src/mon/OSDMonitor.cc
@@ -2201,6 +2201,18 @@ bool OSDMonitor::preprocess_command(MMonCommand *m)
     }
     rdata.append(ds);
   }
+  else if (prefix == "osd blocked-by") {
+    const PGMap &pgm = mon->pgmon()->pg_map;
+    if (f) {
+      f->open_object_section("osd_blocked_by");
+      pgm.dump_osd_blocked_by_stats(f.get());
+      f->close_section();
+      f->flush(ds);
+    } else {
+      pgm.print_osd_blocked_by_stats(&ds);
+    }
+    rdata.append(ds);
+  }
   else if (prefix == "osd dump" ||
 	   prefix == "osd tree" ||
 	   prefix == "osd ls" ||
diff --git a/src/mon/PGMap.cc b/src/mon/PGMap.cc
index dbe78e400ec..4c5c6ba3c59 100644
--- a/src/mon/PGMap.cc
+++ b/src/mon/PGMap.cc
@@ -843,6 +843,34 @@ void PGMap::print_osd_perf_stats(std::ostream *ss) const
   (*ss) << tab;
 }
 
+void PGMap::dump_osd_blocked_by_stats(Formatter *f) const
+{
+  f->open_array_section("osd_blocked_by_infos");
+  for (ceph::unordered_map<int,int>::const_iterator i = blocked_by_sum.begin();
+       i != blocked_by_sum.end();
+       ++i) {
+    f->open_object_section("osd");
+    f->dump_int("id", i->first);
+    f->dump_int("num_blocked", i->second);
+    f->close_section();
+  }
+  f->close_section();
+}
+void PGMap::print_osd_blocked_by_stats(std::ostream *ss) const
+{
+  TextTable tab;
+  tab.define_column("osd", TextTable::LEFT, TextTable::RIGHT);
+  tab.define_column("num_blocked", TextTable::LEFT, TextTable::RIGHT);
+  for (ceph::unordered_map<int,int>::const_iterator i = blocked_by_sum.begin();
+       i != blocked_by_sum.end();
+       ++i) {
+    tab << i->first;
+    tab << i->second;
+    tab << TextTable::endrow;
+  }
+  (*ss) << tab;
+}
+
 void PGMap::recovery_summary(Formatter *f, ostream *out,
                              const pool_stat_t& delta_sum) const
 {