Ensure you have XHProf configured on your server to enable Profiling . Go to Site Administration > Development > Make Test Course and create an M-sized test course. Site Administration > Development > Profiling Check "Enable profiling" Set "Profile these" to "/lib/ajax/service.php" Save changes Load the test course you created. This will trigger a call to core_courseformat_get_state via /lib/ajax/service.php Go to Site Administration > Development > Profiling Runs Select the profile of /lib/ajax/service.php with the most function calls. This should be the profile of core_courseformat_get_state. Make sure to click the link in the "Date" column, not the "URL" column. Follow "View profiling details" Confirm "core_courseformat\external\get_state::execute" exists in the "Function Name" column. If not, you are looking at the wrong profile. Click "display all" at the bottom of the page to list all profiled functions. Find the row with "completion_info::is_tracked_user" in the "Function name" column (Press Ctrl+F and type "is_tracked"). Confirm the value in the "Calls" column is 1 Before fix : The value is around 300.