diff --git a/lib/thirdpartylibs.xml b/lib/thirdpartylibs.xml
index f325724bcc1..7f9d7d3a24b 100644
--- a/lib/thirdpartylibs.xml
+++ b/lib/thirdpartylibs.xml
@@ -158,7 +158,7 @@
     <location>xhprof</location>
     <name>XHProf</name>
     <license>Apache</license>
-    <version>2.2.3</version>
+    <version>2.3.5</version>
     <licenseversion>2.0</licenseversion>
   </library>
   <library>
diff --git a/lib/xhprof/readme_moodle.txt b/lib/xhprof/readme_moodle.txt
index 16e0f575f22..5d2fba90e5b 100644
--- a/lib/xhprof/readme_moodle.txt
+++ b/lib/xhprof/readme_moodle.txt
@@ -1,4 +1,4 @@
-Description of XHProf 2.2.3 library/viewer import into Moodle
+Description of XHProf 2.3.5 library/viewer import into Moodle
 
 Removed (commit #1):
  * examples - examples dir removed completely
@@ -40,4 +40,4 @@ TODO:
 20201012 - MDL-67081 - Brendan Heywood (brendanheywood): Support selective profiles from CLI
 20201210 - MDL-70297 - Ilya Tregubov (ilyatregubov): Upgrade to 2.2.3 release;
 20210209 - MDL-70525 - Tomo Tsuyuki (tomotsuyuki): Allow huge number of values
-
+20211209 - MDL-71705 - Ilya Tregubov (ilyatregubov): Upgrade to 2.3.5 release;
diff --git a/lib/xhprof/xhprof_html/callgraph.php b/lib/xhprof/xhprof_html/callgraph.php
index 22d1c2f261f..5076eab9ef5 100644
--- a/lib/xhprof/xhprof_html/callgraph.php
+++ b/lib/xhprof/xhprof_html/callgraph.php
@@ -29,6 +29,15 @@
  * @author Changhao Jiang (cjiang@facebook.com)
  */
 
+// Start moodle modification: moodleize this script.
+require_once(dirname(dirname(dirname(dirname(__FILE__)))).'/config.php');
+require_once($CFG->libdir . '/xhprof/xhprof_moodle.php');
+require_login();
+require_capability('moodle/site:config', context_system::instance());
+raise_memory_limit(MEMORY_HUGE);
+\core\session\manager::write_close();
+// End moodle modification.
+
 // by default assume that xhprof_html & xhprof_lib directories
 // are at the same level.
 $GLOBALS['XHPROF_LIB_ROOT'] = dirname(__FILE__) . '/../xhprof_lib';
@@ -78,7 +87,10 @@ if (!array_key_exists($type, $xhprof_legal_image_types)) {
   $type = $params['type'][1]; // default image type.
 }
 
-$xhprof_runs_impl = new XHProfRuns_Default();
+// Start moodle modification: use own XHProfRuns implementation.
+// $xhprof_runs_impl = new XHProfRuns_Default();
+$xhprof_runs_impl = new moodle_xhprofrun();
+// End moodle modification.
 
 if (!empty($run)) {
   // single run call graph image generation
diff --git a/lib/xhprof/xhprof_html/css/xhprof.css b/lib/xhprof/xhprof_html/css/xhprof.css
index c3abf8622b7..250b9903fc3 100644
--- a/lib/xhprof/xhprof_html/css/xhprof.css
+++ b/lib/xhprof/xhprof_html/css/xhprof.css
@@ -13,6 +13,12 @@
  *  limitations under the License.
  */
 
+/* Start moodle modification: add basic, smaller, font specs */
+body, p, table, li {
+    font: normal normal normal 13px/1.231 arial, helvetica, clean, sans-serif;
+}
+/* End moodle modification */
+
 td.sorted {
   color:#0000FF;
 }
diff --git a/lib/xhprof/xhprof_html/index.php b/lib/xhprof/xhprof_html/index.php
index f21d32fd5d0..80e7821fe92 100644
--- a/lib/xhprof/xhprof_html/index.php
+++ b/lib/xhprof/xhprof_html/index.php
@@ -31,6 +31,15 @@
 //             Changhao Jiang
 //
 
+// Start moodle modification: moodleize this script.
+require_once(dirname(dirname(dirname(dirname(__FILE__)))).'/config.php');
+require_once($CFG->libdir . '/xhprof/xhprof_moodle.php');
+require_login();
+require_capability('moodle/site:config', context_system::instance());
+raise_memory_limit(MEMORY_HUGE);
+\core\session\manager::write_close();
+// End moodle modification.
+
 // by default assume that xhprof_html & xhprof_lib directories
 // are at the same level.
 $GLOBALS['XHPROF_LIB_ROOT'] = dirname(__FILE__) . '/../xhprof_lib';
@@ -80,7 +89,10 @@ $vbbar = ' class="vbbar"';
 $vrbar = ' class="vrbar"';
 $vgbar = ' class="vgbar"';
 
-$xhprof_runs_impl = new XHProfRuns_Default();
+// Start moodle modification: use own XHProfRuns implementation.
+// $xhprof_runs_impl = new XHProfRuns_Default();
+$xhprof_runs_impl = new moodle_xhprofrun();
+// End moodle modification.
 
 displayXHProfReport($xhprof_runs_impl, $params, $source, $run, $wts,
                     $symbol, $sort, $run1, $run2);
diff --git a/lib/xhprof/xhprof_html/typeahead.php b/lib/xhprof/xhprof_html/typeahead.php
index ba98e0c383d..54022257430 100644
--- a/lib/xhprof/xhprof_html/typeahead.php
+++ b/lib/xhprof/xhprof_html/typeahead.php
@@ -21,12 +21,22 @@
  *             Changhao Jiang
  */
 
+// Start moodle modification: moodleize this script.
+require_once(dirname(dirname(dirname(dirname(__FILE__)))).'/config.php');
+require_once($CFG->libdir . '/xhprof/xhprof_moodle.php');
+require_login();
+require_capability('moodle/site:config', context_system::instance());
+\core\session\manager::write_close();
+// End moodle modification.
+
 // by default assume that xhprof_html & xhprof_lib directories
 // are at the same level.
 $GLOBALS['XHPROF_LIB_ROOT'] = dirname(__FILE__) . '/../xhprof_lib';
 
 require_once $GLOBALS['XHPROF_LIB_ROOT'].'/display/xhprof.php';
 
-$xhprof_runs_impl = new XHProfRuns_Default();
+// Start moodle modification: use own XHProfRuns implementation.
+$xhprof_runs_impl = new moodle_xhprofrun();
+// End moodle modification.
 
 require_once $GLOBALS['XHPROF_LIB_ROOT'].'/display/typeahead_common.php';
diff --git a/lib/xhprof/xhprof_lib/utils/callgraph_utils.php b/lib/xhprof/xhprof_lib/utils/callgraph_utils.php
index 90f4c31a202..3a70aa0b06e 100644
--- a/lib/xhprof/xhprof_lib/utils/callgraph_utils.php
+++ b/lib/xhprof/xhprof_lib/utils/callgraph_utils.php
@@ -107,7 +107,11 @@ function xhprof_generate_image_by_dot($dot_script, $type) {
        2 => array("pipe", "w")
        );
 
-  $cmd = " dot -T".$type;
+  // Start moodle modification: use $CFG->pathtodot for executing this.
+  // $cmd = " dot -T".$type;
+  global $CFG;
+  $cmd = (!empty($CFG->pathtodot) ? $CFG->pathtodot : 'dot') . ' -T' . $type;
+  // End moodle modification.
 
   $process = proc_open( $cmd, $descriptorspec, $pipes, sys_get_temp_dir(), array( 'PATH' => getenv( 'PATH' ) ) );
   if (is_resource($process)) {