diff --git a/repos/os/src/app/top/main.cc b/repos/os/src/app/top/main.cc
index f471e25c8..0a6997d25 100644
--- a/repos/os/src/app/top/main.cc
+++ b/repos/os/src/app/top/main.cc
@@ -82,14 +82,16 @@ struct Trace_subject_registry
 
 		bool _reconstruct_trace_connection = false;
 
+		template <typename FN>
 		unsigned update_subjects(Genode::Pd_session &pd,
-		                         Genode::Trace::Connection &trace)
+		                         Genode::Trace::Connection &trace,
+		                         FN const &fn)
 		{
 			Genode::Ram_quota ram_quota;
 
 			do {
 				try {
-					return trace.subjects(_subjects, MAX_SUBJECTS);
+					return trace.for_each_subject_info(fn);
 				} catch (Genode::Out_of_ram) {
 					trace.upgrade_ram(4096);
 				}
@@ -107,17 +109,7 @@ struct Trace_subject_registry
 		void update(Genode::Pd_session &pd, Genode::Trace::Connection &trace,
 		            Genode::Allocator &alloc)
 		{
-			unsigned const num_subjects = update_subjects(pd, trace);
-
-			if (num_subjects == MAX_SUBJECTS)
-				Genode::error("Not enough memory for all threads - "
-				              "calculated utilization is not sane nor "
-				              "complete !", num_subjects);
-
-			/* add and update existing entries */
-			for (unsigned i = 0; i < num_subjects; i++) {
-
-				Genode::Trace::Subject_id const id = _subjects[i];
+			update_subjects(pd, trace, [&](Genode::Trace::Subject_id const &id, Genode::Trace::Subject_info const &info) {
 
 				Entry *e = _lookup(id);
 				if (!e) {
@@ -125,7 +117,7 @@ struct Trace_subject_registry
 					_entries.insert(e);
 				}
 
-				e->update(trace.subject_info(id));
+				e->update(info);
 
 				/* remove dead threads which did not run in the last period */
 				if (e->info.state() == Genode::Trace::Subject_info::DEAD &&
@@ -135,7 +127,7 @@ struct Trace_subject_registry
 					_entries.remove(e);
 					Genode::destroy(alloc, e);
 				}
-			}
+			});
 
 			if (_reconstruct_trace_connection)
 				throw Genode::Out_of_ram();