MDL-55292 performance: Allow Tideways profiler extension.

PHP7 doesn't have any default XHProf support and all other
investigated forks don't have stable PHP7.  Tideways is under
active development and is easy to install.  The data format
is compatible with XHProf so it is a drop-in replacement in that way.

admin/settings/development.php

@@ -32,7 +32,7 @@ if ($hassiteconfig) { // speedup for non-admins, add all caps used on this page
     $ADMIN->add('development', $temp);
 
     // "Profiling" settingpage (conditionally if the 'xhprof' extension is available only).
-    $xhprofenabled = extension_loaded('xhprof') && function_exists('xhprof_enable');
+    $xhprofenabled = extension_loaded('xhprof') || extension_loaded('tideways');
     $temp = new admin_settingpage('profiling', new lang_string('profiling', 'admin'), 'moodle/site:config', !$xhprofenabled);
     // Main profiling switch.
     $temp->add(new admin_setting_configcheckbox('profilingenabled', new lang_string('profilingenabled', 'admin'), new lang_string('profilingenabled_help', 'admin'), false));

admin/tool/profiling/settings.php

@@ -26,6 +26,7 @@
 defined('MOODLE_INTERNAL') || die;
 
 // profiling tool, added to development
-if (extension_loaded('xhprof') && function_exists('xhprof_enable') && (!empty($CFG->profilingenabled) || !empty($CFG->earlyprofilingenabled))) {
-    $ADMIN->add('development', new admin_externalpage('toolprofiling', get_string('pluginname', 'tool_profiling'), "$CFG->wwwroot/$CFG->admin/tool/profiling/index.php", 'moodle/site:config'));
+if ((extension_loaded('xhprof') || extension_loaded('tideways')) && (!empty($CFG->profilingenabled) || !empty($CFG->earlyprofilingenabled))) {
+    $ADMIN->add('development', new admin_externalpage('toolprofiling', get_string('pluginname', 'tool_profiling'),
+            "$CFG->wwwroot/$CFG->admin/tool/profiling/index.php", 'moodle/site:config'));
 }

lib/xhprof/readme_moodle.txt

@@ -36,3 +36,4 @@ TODO:
 20101122 - MDL-24600 - Eloy Lafuente (stronk7): Original import of 0.9.2 release
 20110318 - MDL-26891 - Eloy Lafuente (stronk7): Implemented earlier profiling runs
 20130621 - MDL-39733 - Eloy Lafuente (stronk7): Export & import of profiling runs
+20160721 - MDL-55292 - Russell Smith (mr-russ): Add support for tideways profiler collection for PHP7

lib/xhprof/xhprof_moodle.php

@@ -69,7 +69,7 @@ function profiling_start() {
     global $CFG, $SESSION, $SCRIPT;
 
     // If profiling isn't available, nothing to start
-    if (!extension_loaded('xhprof') || !function_exists('xhprof_enable')) {
+    if (!extension_loaded('xhprof') && !extension_loaded('tideways')) {
         return false;
     }
 
@@ -146,7 +146,11 @@ function profiling_start() {
 
     // Arrived here, the script is going to be profiled, let's do it
     $ignore = array('call_user_func', 'call_user_func_array');
-    xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY, array('ignored_functions' =>  $ignore));
+    if (extension_loaded('tideways')) {
+        tideways_enable(TIDEWAYS_FLAGS_CPU + TIDEWAYS_FLAGS_MEMORY, array('ignored_functions' =>  $ignore));
+    } else {
+        xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY, array('ignored_functions' => $ignore));
+    }
     profiling_is_running(true);
 
     // Started, return true
@@ -160,7 +164,7 @@ function profiling_stop() {
     global $CFG, $DB, $SCRIPT;
 
     // If profiling isn't available, nothing to stop
-    if (!extension_loaded('xhprof') || !function_exists('xhprof_enable')) {
+    if (!extension_loaded('xhprof') && !extension_loaded('tideways')) {
         return false;
     }
 
@@ -179,7 +183,11 @@ function profiling_stop() {
 
     // Arrived here, profiling is running, stop and save everything
     profiling_is_running(false);
-    $data = xhprof_disable();
+    if (extension_loaded('tideways')) {
+        $data = tideways_disable();
+    } else {
+        $data = xhprof_disable();
+    }
 
     // We only save the run after ensuring the DB table exists
     // (this prevents problems with profiling runs enabled in