diff --git a/core/includes/common.inc b/core/includes/common.inc
index 11f8a9d..bab5257 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -9,30 +9,21 @@
  */
 
 use Drupal\Component\Serialization\Json;
-use Drupal\Component\Serialization\Yaml;
-use Drupal\Component\Serialization\Exception\InvalidDataTypeException;
 use Drupal\Component\Utility\Bytes;
 use Drupal\Component\Utility\Crypt;
 use Drupal\Component\Utility\Html;
-use Drupal\Component\Utility\Number;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Component\Utility\SortArray;
 use Drupal\Component\Utility\String;
-use Drupal\Component\Utility\Tags;
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Cache\Cache;
-use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Site\Settings;
 use Drupal\Core\Url;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpFoundation\Request;
-use Drupal\Core\PhpStorage\PhpStorageFactory;
 use Drupal\Component\Utility\NestedArray;
-use Drupal\Core\Datetime\DrupalDateTime;
-use Drupal\Core\Routing\GeneratorNotInitializedException;
 use Drupal\Core\Template\Attribute;
 use Drupal\Core\Render\Element;
-use Drupal\Core\Session\AnonymousUserSession;
 
 /**
  * @defgroup php_wrappers PHP wrapper functions
diff --git a/core/lib/Drupal/Component/Serialization/Yaml.php b/core/lib/Drupal/Component/Serialization/Yaml.php
index 7d0f0c5..058300e 100644
--- a/core/lib/Drupal/Component/Serialization/Yaml.php
+++ b/core/lib/Drupal/Component/Serialization/Yaml.php
@@ -8,6 +8,9 @@
 namespace Drupal\Component\Serialization;
 
 use Drupal\Component\Serialization\Exception\InvalidDataTypeException;
+use Drupal\Component\Serialization\YamlPecl;
+use Drupal\Component\Serialization\YamlSymfony;
+use Drupal\Core\Site\Settings;
 use Symfony\Component\Yaml\Yaml as Symfony;
 
 /**
@@ -16,27 +19,55 @@
 class Yaml implements SerializationInterface {
 
   /**
+   * The YAML implementation to use.
+   *
+   * @var \Drupal\Component\Serialization\SerializationInterface
+   */
+  protected static $instance;
+
+  /**
+   * Determines the optimal implementation to use for encoding and parsing Yaml.
+   *
+   * The selection is made based on the enabled PHP extensions, with the most
+   * performant available option chosen.
+   */
+  public function __construct() {
+    if (isset(static::$instance)) {
+      return;
+    }
+    $settings = Settings::getInstance();
+    // If there is a settings.php override, use that.
+    if ($settings && ($class = $settings->get('yaml_parser_class'))) {
+      static::$instance = new $class();
+    }
+    // If the PECL YAML extension installed, use that.
+    elseif (extension_loaded('yaml')) {
+      static::$instance = new YamlPecl();
+    }
+    else {
+      // Otherwise, fallback to the Symfony implementation.
+      static::$instance = new YamlSymfony();
+    }
+  }
+
+  /**
    * {@inheritdoc}
    */
   public static function encode($data) {
-    try {
-      return Symfony::dump($data, PHP_INT_MAX, 2, TRUE);
-    }
-    catch (\Exception $e) {
-      throw new InvalidDataTypeException($e->getMessage(), $e->getCode(), $e);
+    if (!isset(static::$instance)) {
+      new static();
     }
+    return static::$instance->encode($data);
   }
 
   /**
    * {@inheritdoc}
    */
   public static function decode($raw) {
-    try {
-      return Symfony::parse($raw, TRUE);
-    }
-    catch (\Exception $e) {
-      throw new InvalidDataTypeException($e->getMessage(), $e->getCode(), $e);
+    if (!isset(static::$instance)) {
+      new static();
     }
+    return static::$instance->decode($raw);
   }
 
   /**
diff --git a/core/lib/Drupal/Component/Serialization/YamlPecl.php b/core/lib/Drupal/Component/Serialization/YamlPecl.php
new file mode 100644
index 0000000..03a8a31
--- /dev/null
+++ b/core/lib/Drupal/Component/Serialization/YamlPecl.php
@@ -0,0 +1,91 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Serialization\YamlPecl.
+ */
+
+namespace Drupal\Component\Serialization;
+
+use Drupal\Component\Serialization\Exception\InvalidDataTypeException;
+
+/**
+ * Default serialization for YAML using the PECL extension.
+ */
+class YamlPecl implements SerializationInterface {
+
+  /**
+   * Sets defaults according to Drupal coding standards.
+   */
+  public function __construct() {
+    ini_set('yaml.output_indent', 2);
+    // Do not break lines at 80 characters.
+    ini_set('yaml.output_width', -1);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function encode($data) {
+    return yaml_emit($data, YAML_UTF8_ENCODING, YAML_LN_BREAK);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function decode($raw) {
+    // @todo Use ErrorExceptions.
+    // @see https://drupal.org/node/1247666
+    set_error_handler(array(__CLASS__, 'errorHandler'));
+    $ndocs = 0;
+    $data = yaml_parse($raw, 0, $ndocs, [
+      YAML_BOOL_TAG => '\Drupal\Component\Serialization\YamlPecl::applyBooleanCallbacks',
+    ]);
+    restore_error_handler();
+    return $data;
+  }
+
+  /**
+   * Temporary error handler for YamlPecl::decode().
+   */
+  public static function errorHandler($severity, $message, $file, $line) {
+    restore_error_handler();
+    throw new InvalidDataTypeException($message, $severity);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getFileExtension() {
+    return 'yml';
+  }
+
+  /**
+   * Applies callbacks after parsing to ignore 1.1 style booleans.
+   *
+   * @param mixed $value
+   *   Value from YAML file.
+   * @param string $tag
+   *   Tag that triggered the callback.
+   * @param int $flags
+   *   Scalar entity style flags.
+   *
+   * @return string|bool
+   *   FALSE, false, TRUE and true are returned as booleans, everything else is
+   *   returned as a string.
+   */
+  public static function applyBooleanCallbacks($value, $tag, $flags) {
+    // YAML 1.1 spec dictates that 'Y', 'N', 'y' and 'n' are booleans, we want
+    // the 1.2 behaviour so we only case 'false', 'FALSE', 'true' OR 'TRUE' as
+    // booleans.
+    if (!in_array(strtolower($value), ['false', 'true'], TRUE)) {
+      return $value;
+    }
+    $map = [
+      'false' => FALSE,
+      'true' => TRUE,
+    ];
+    return $map[strtolower($value)];
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Serialization/Yaml.php b/core/lib/Drupal/Component/Serialization/YamlSymfony.php
similarity index 88%
copy from core/lib/Drupal/Component/Serialization/Yaml.php
copy to core/lib/Drupal/Component/Serialization/YamlSymfony.php
index 7d0f0c5..2d71b7c 100644
--- a/core/lib/Drupal/Component/Serialization/Yaml.php
+++ b/core/lib/Drupal/Component/Serialization/YamlSymfony.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\Component\Serialization\Yaml.
+ * Contains \Drupal\Component\Serialization\YamlSymfony.
  */
 
 namespace Drupal\Component\Serialization;
@@ -13,7 +13,7 @@
 /**
  * Default serialization for YAML using the Symfony component.
  */
-class Yaml implements SerializationInterface {
+class YamlSymfony implements SerializationInterface {
 
   /**
    * {@inheritdoc}
diff --git a/core/lib/Drupal/Core/Serialization/Yaml.php b/core/lib/Drupal/Core/Serialization/Yaml.php
new file mode 100644
index 0000000..5aa3fbb
--- /dev/null
+++ b/core/lib/Drupal/Core/Serialization/Yaml.php
@@ -0,0 +1,79 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Serialization\Yaml.
+ */
+
+namespace Drupal\Component\Serialization;
+
+use Drupal\Component\Utility\Settings;
+
+/**
+ * Default serialization for YAML.
+ *
+ * Automatically uses the optimal YAML implementation, unless overridden in
+ * Settings.
+ */
+class Yaml implements SerializationInterface {
+
+  /**
+   * The YAML implementation to use.
+   *
+   * @var \Drupal\Component\Serialization\SerializationInterface
+   */
+  protected static $instance;
+
+  /**
+   * Determines the optimal implementation to use for encoding and parsing Yaml.
+   *
+   * The selection is made based on the enabled PHP extensions, with the most
+   * performant available option chosen.
+   */
+  public function __construct() {
+    if (isset(static::$instance)) {
+      return;
+    }
+    $settings = Settings::getSingleton();
+    // If there is a settings.php override, use that.
+    if ($settings && ($class = $settings->get('yaml_parser_class'))) {
+      static::$instance = new $class();
+    }
+    // If the PECL YAML extension installed, use that.
+    elseif (extension_loaded('yaml')) {
+      static::$instance = new YamlPecl();
+    }
+    else {
+      // Otherwise, fallback to the Symfony implementation.
+      static::$instance = new YamlSymfony();
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function encode($data) {
+    if (!isset(static::$instance)) {
+      new static();
+    }
+    return static::$instance->encode($data);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function decode($raw) {
+    if (!isset(static::$instance)) {
+      new static();
+    }
+    return static::$instance->decode($raw);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getFileExtension() {
+    return 'yml';
+  }
+
+}
diff --git a/core/modules/system/tests/fixtures/common_test.info.txt b/core/modules/system/tests/fixtures/common_test.info.txt
index 7e57dfe..ff535b1 100644
--- a/core/modules/system/tests/fixtures/common_test.info.txt
+++ b/core/modules/system/tests/fixtures/common_test.info.txt
@@ -4,4 +4,4 @@ type: module
 description: 'testing info file parsing'
 simple_string: 'A simple string'
 version: "VERSION"
-double_colon: dummyClassName::
+double_colon: dummyClassName::foo
diff --git a/core/modules/views/config/schema/views.data_types.schema.yml b/core/modules/views/config/schema/views.data_types.schema.yml
index 64ff9c4..7cf0cad 100644
--- a/core/modules/views/config/schema/views.data_types.schema.yml
+++ b/core/modules/views/config/schema/views.data_types.schema.yml
@@ -365,7 +365,6 @@ views_argument:
       label: 'Override title'
     title:
       type: label
-      label: 'Title'
       label: 'Overridden title'
     default_argument_type:
       type: string
diff --git a/core/tests/Drupal/Tests/Component/Serialization/YamlTest.php b/core/tests/Drupal/Tests/Component/Serialization/YamlTest.php
new file mode 100644
index 0000000..a6dc382
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Serialization/YamlTest.php
@@ -0,0 +1,152 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Component\Serialization\YamlTest.
+ */
+
+namespace Drupal\Tests\Component\Serialization;
+
+use Drupal\Component\Serialization\YamlSymfony;
+use Drupal\Component\Serialization\YamlPecl;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests the \Drupal\Component\Serialization\Yaml* implementations.
+ *
+ * @group Drupal
+ * @group Serialization
+ */
+class YamlTest extends UnitTestCase {
+
+  protected function setUp() {
+    if (!extension_loaded('yaml')) {
+      $this->markTestSkipped('The PECL Yaml extension is not available.');
+    }
+  }
+
+  /**
+   * Tests encoding with Symfony and decoding with PECL and vice versa.
+   *
+   * @dataProvider providerYamlData
+   * @covers \Drupal\Component\Serialization\Yaml::encode
+   * @covers \Drupal\Component\Serialization\Yaml::decode
+   * @covers \Drupal\Component\Serialization\YamlPecl::encode
+   * @covers \Drupal\Component\Serialization\YamlPecl::decode
+   * @covers \Drupal\Component\Serialization\YamlSymfony::encode
+   * @covers \Drupal\Component\Serialization\YamlSymfony::decode
+   */
+  public function testEncodeDecode($data, $parser_class, $dumper_class) {
+    $dumper = new $dumper_class;
+    $parser = new $parser_class;
+
+    $dumped = $dumper->encode($data);
+
+    $parsed = $parser->decode($dumped);
+
+    $this->assertEquals($data, $parsed);
+  }
+
+  /**
+   * Tests decoding YAML node anchors with both Symfony and PECL.
+   *
+   * @dataProvider providerYamlNodeAnchors
+   */
+  public function testDecodeNodeAnchors($data) {
+    $symfony = new YamlSymfony();
+    $pecl = new YamlPecl();
+    $this->assertEquals($symfony->decode($data), $pecl->decode($data));
+  }
+
+  /**
+   * Data provider for YAML instance tests.
+   *
+   * @return array
+   */
+  public function providerYamlData() {
+    $object = array(
+      'foo' => 'bar',
+      'id' => 'schnitzel',
+      'ponies' => array('nope', 'thanks'),
+      'how' => array(
+        'about' => 'if',
+        'i' => 'ask',
+        'nicely'
+      ),
+      'the' => array(
+        'answer' => array(
+          'still' => 'would',
+          'be' => 'Y',
+        ),
+      ),
+      'how_many_times' => 123,
+      'should_i_ask' => FALSE,
+      1,
+      FALSE,
+      array(1, FALSE),
+      array(10),
+      array(0 => '123456'),
+    );
+
+    // Test parsing with Symfony and dumping with PECL.
+    $data[] = array(
+      $object,
+      'Drupal\Component\Serialization\YamlSymfony',
+      'Drupal\Component\Serialization\YamlPecl'
+    );
+    // Test parsing with PECL and dumping with Symfony.
+    $data[] = array(
+      $object,
+      'Drupal\Component\Serialization\YamlPecl',
+      'Drupal\Component\Serialization\YamlSymfony'
+    );
+    return $data;
+  }
+
+  /**
+   * Data provider for YAML instance tests.
+   *
+   * @return array
+   */
+  public function providerYamlNodeAnchors() {
+    $yaml = <<<EOF
+jquery.ui:
+  version: &jquery_ui 1.10.2
+
+jquery.ui.accordion:
+  version: *jquery_ui
+EOF;
+    $data[] = array($yaml);
+    return $data;
+  }
+
+  /**
+   * Tests all YAML files are decoded in the same way with both Symfony and PECL.
+   *
+   * @dataProvider providerYamlFilesInCore
+   */
+  public function testYamlFilesInCore($file) {
+    $data = file_get_contents($file);
+    $symfony = new YamlSymfony();
+    $pecl = new YamlPecl();
+    $this->assertEquals($symfony->decode($data), $pecl->decode($data));
+  }
+
+  /**
+   * Data provider for YAML files in core test.
+   * @return array
+   */
+  public function providerYamlFilesInCore() {
+    $files = array();
+    $dirs = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator(__DIR__ . '/../../../../../', \RecursiveDirectoryIterator::FOLLOW_SYMLINKS));
+    foreach ($dirs as $dir) {
+      $pathname = $dir->getPathname();
+      // Exclude vendor.
+      if ($dir->getExtension() == 'yml' && strpos($pathname, '/../../../../../vendor') === FALSE) {
+        $files[] = array($dir->getRealPath());
+      }
+    }
+    return $files;
+  }
+
+}