diff --git a/frontend_tests/node_tests/presence_list_performance.js b/frontend_tests/node_tests/presence_list_performance.js
index 4e95574edd..94a7a52b04 100644
--- a/frontend_tests/node_tests/presence_list_performance.js
+++ b/frontend_tests/node_tests/presence_list_performance.js
@@ -45,7 +45,7 @@ activity.presence_info = {
 };
 
 (function test_presence_list_full_update() {
-    var users = activity._update_users();
+    var users = activity.update_users();
     assert.deepEqual(users, [
         { name: 'Fred Flintstone',
           email: 'fred@zulip.com',
@@ -86,7 +86,7 @@ activity.presence_info = {
     };
     activity.presence_info['alice@zulip.com'] = users['alice@zulip.com'];
 
-    users = activity._update_users(users);
+    users = activity.update_users(users);
     assert.deepEqual(users, [
         { name: 'Alice Smith',
           email: 'alice@zulip.com',
@@ -105,7 +105,7 @@ activity.presence_info = {
         'mark@zulip.com': {status: 'active'}
     };
     activity.presence_info['mark@zulip.com'] = users['mark@zulip.com'];
-    users = activity._update_users(users);
+    users = activity.update_users(users);
     assert.deepEqual(users, [
         { name: 'Marky Mark',
           email: 'mark@zulip.com',
diff --git a/static/js/activity.js b/static/js/activity.js
index 3a16e89678..89e0401f83 100644
--- a/static/js/activity.js
+++ b/static/js/activity.js
@@ -215,7 +215,7 @@ function filter_and_sort(users) {
 }
 exports._filter_and_sort = filter_and_sort;
 
-function actually_update_users(user_list) {
+exports.update_users = function (user_list) {
     if (page_params.domain === 'mit.edu') {
         return;  // MIT realm doesn't have a presence list
     }
@@ -268,20 +268,10 @@ function actually_update_users(user_list) {
 
     // Return updated users: useful for testing user performance fix
     return user_info;
-}
-exports._update_users = actually_update_users;
-
-// The function actually_update_users() can be pretty expensive for realms with lots
-// of users.  Not only is there more work to do in terms of rendering the user list, but
-// we also get more updates.  Large realms have reported lags while typing in the compose
-// box, and there's strong evidence that this is caused by user list updates.  This isn't a
-// perfect solution, but it should remove some pain, and there's no real harm in waiting five
-// seconds to update user activity.
-var update_users = _.throttle(actually_update_users, 5000);
-
+};
 
 function actually_update_users_for_search() {
-    actually_update_users();
+    exports.update_users();
     resize.resize_page_components();
 }
 
@@ -385,7 +375,7 @@ function focus_ping() {
                     exports.presence_info[this_email] = status_from_timestamp(data.server_timestamp, presence);
                 }
             });
-            update_users();
+            exports.update_users();
             exports.update_huddles();
         }
     });
@@ -431,7 +421,7 @@ exports.set_user_statuses = function (users, server_time) {
         updated_users[email] = status;
     });
 
-    update_users(updated_users);
+    exports.update_users(updated_users);
     exports.update_huddles();
 };