diff --git a/Gemfile b/Gemfile
index 715ce2bc6c228f5b78a9caa5031f14cf61d4c509..7a5b32a447d626e4fcd28efb7717cbc7b56a4e6c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -264,6 +264,18 @@ gem 'gettext_i18n_rails', '~> 1.8.0'
 gem 'gettext_i18n_rails_js', '~> 1.2.0'
 gem 'gettext', '~> 3.2.2', require: false, group: :development
 
+# Perf bar
+gem 'peek', '~> 1.0.1'
+gem 'peek-gc', '~> 0.0.2'
+gem 'peek-host', '~> 1.0.0'
+gem 'peek-mysql2', '~> 1.1.0', group: :mysql
+gem 'peek-performance_bar', '~> 1.2.1'
+gem 'peek-pg', '~> 1.3.0'
+gem 'peek-rblineprof', '~> 0.2.0'
+gem 'pygments.rb', require: false
+gem 'peek-redis', '~> 1.2.0'
+gem 'peek-sidekiq', '~> 1.0.3'
+
 # Metrics
 group :metrics do
   gem 'allocations', '~> 1.0', require: false, platform: :mri
diff --git a/Gemfile.lock b/Gemfile.lock
index d34b84df5e62b6544132e6543390bd2835855502..4c5c3db40c90db8dcb8b43ad4f513bdbb16b29a8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -56,6 +56,7 @@ GEM
     asciidoctor-plantuml (0.0.7)
       asciidoctor (~> 1.5)
     ast (2.3.0)
+    atomic (1.1.99)
     attr_encrypted (3.0.3)
       encryptor (~> 3.0.0)
     attr_required (1.0.0)
@@ -131,6 +132,8 @@ GEM
     coffee-script-source (1.10.0)
     colorize (0.7.7)
     concurrent-ruby (1.0.5)
+    concurrent-ruby-ext (1.0.5)
+      concurrent-ruby (= 1.0.5)
     connection_pool (2.2.1)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
@@ -548,6 +551,36 @@ GEM
     parser (2.4.0.0)
       ast (~> 2.2)
     path_expander (1.0.1)
+    peek (1.0.1)
+      concurrent-ruby (>= 0.9.0)
+      concurrent-ruby-ext (>= 0.9.0)
+      railties (>= 4.0.0)
+    peek-gc (0.0.2)
+      peek
+    peek-host (1.0.0)
+      peek
+    peek-mysql2 (1.1.0)
+      atomic (>= 1.0.0)
+      mysql2
+      peek
+    peek-performance_bar (1.2.1)
+      peek (>= 0.1.0)
+    peek-pg (1.3.0)
+      concurrent-ruby
+      concurrent-ruby-ext
+      peek
+      pg
+    peek-rblineprof (0.2.0)
+      peek
+      rblineprof
+    peek-redis (1.2.0)
+      atomic (>= 1.0.0)
+      peek
+      redis
+    peek-sidekiq (1.0.3)
+      atomic (>= 1.0.0)
+      peek
+      sidekiq
     pg (0.18.4)
     po_to_json (1.0.1)
       json (>= 1.6.0)
@@ -575,6 +608,8 @@ GEM
       pry (~> 0.10)
     pry-rails (0.3.5)
       pry (>= 0.9.10)
+    pygments.rb (1.1.2)
+      multi_json (>= 1.0.0)
     pyu-ruby-sasl (0.0.3.3)
     rack (1.6.5)
     rack-accept (0.4.5)
@@ -999,12 +1034,22 @@ DEPENDENCIES
   omniauth_crowd (~> 2.2.0)
   org-ruby (~> 0.9.12)
   paranoia (~> 2.2)
+  peek (~> 1.0.1)
+  peek-gc (~> 0.0.2)
+  peek-host (~> 1.0.0)
+  peek-mysql2 (~> 1.1.0)
+  peek-performance_bar (~> 1.2.1)
+  peek-pg (~> 1.3.0)
+  peek-rblineprof (~> 0.2.0)
+  peek-redis (~> 1.2.0)
+  peek-sidekiq (~> 1.0.3)
   pg (~> 0.18.2)
   poltergeist (~> 1.9.0)
   premailer-rails (~> 1.9.0)
   prometheus-client-mmap (~> 0.7.0.beta5)
   pry-byebug (~> 3.4.1)
   pry-rails (~> 0.3.4)
+  pygments.rb
   rack-attack (~> 4.4.1)
   rack-cors (~> 0.4.0)
   rack-oauth2 (~> 1.2.1)
diff --git a/app/assets/javascripts/peek.js b/app/assets/javascripts/peek.js
new file mode 100644
index 0000000000000000000000000000000000000000..4ba23ea1a09020f0c273d5d7a237e916ca99ed22
--- /dev/null
+++ b/app/assets/javascripts/peek.js
@@ -0,0 +1,4 @@
+import 'vendor/jquery.tipsy';
+import 'vendor/peek';
+import 'vendor/peek.performance_bar';
+import 'vendor/peek.rblineprof';
diff --git a/app/assets/javascripts/shortcuts.js b/app/assets/javascripts/shortcuts.js
index 8ac71797c14c01cd478c9c339fe2b3927afeace4..2c7698eb17446c6c001c7ae1101dfda85adff11d 100644
--- a/app/assets/javascripts/shortcuts.js
+++ b/app/assets/javascripts/shortcuts.js
@@ -1,6 +1,8 @@
 /* eslint-disable func-names, space-before-function-paren, no-var, prefer-rest-params, wrap-iife, quotes, prefer-arrow-callback, consistent-return, object-shorthand, no-unused-vars, one-var, one-var-declaration-per-line, no-else-return, comma-dangle, max-len */
 /* global Mousetrap */
 /* global findFileURL */
+import Cookies from 'js-cookie';
+
 import findAndFollowLink from './shortcuts_dashboard_navigation';
 
 (function() {
@@ -14,6 +16,7 @@ import findAndFollowLink from './shortcuts_dashboard_navigation';
       Mousetrap.bind('?', this.onToggleHelp);
       Mousetrap.bind('s', Shortcuts.focusSearch);
       Mousetrap.bind('f', (e => this.focusFilter(e)));
+      Mousetrap.bind('p b', this.onTogglePerfBar);
 
       const $globalDropdownMenu = $('.global-dropdown-menu');
       const $globalDropdownToggle = $('.global-dropdown-toggle');
@@ -53,6 +56,17 @@ import findAndFollowLink from './shortcuts_dashboard_navigation';
       return Shortcuts.toggleHelp(this.enabledHelp);
     };
 
+    Shortcuts.prototype.onTogglePerfBar = function(e) {
+      e.preventDefault();
+      if (Cookies.get('perf_bar_enabled') === 'true') {
+        Cookies.remove('perf_bar_enabled', { path: '/' });
+      }
+      else {
+        Cookies.set('perf_bar_enabled', true, { path: '/' });
+      }
+      return gl.utils.refreshCurrentPage();
+    };
+
     Shortcuts.prototype.toggleMarkdownPreview = function(e) {
       // Check if short-cut was triggered while in Write Mode
       const $target = $(e.target);
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 47ce21d238ba7e3d4cac21b49bb7b47e409492af..01b1462d5ec5335711fc62a787126377eb25ac45 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -18,7 +18,7 @@ class ApplicationController < ActionController::Base
   before_action :ldap_security_check
   before_action :sentry_context
   before_action :default_headers
-  before_action :add_gon_variables
+  before_action :add_gon_variables, unless: -> { request.path.start_with?('/peek') }
   before_action :configure_permitted_parameters, if: :devise_controller?
   before_action :require_email, unless: :devise_controller?
 
@@ -63,6 +63,19 @@ class ApplicationController < ActionController::Base
     end
   end
 
+  def peek_enabled?
+    return false unless Gitlab::PerformanceBar.enabled?
+    return false unless current_user
+
+    if RequestStore.active?
+      if RequestStore.store.key?(:peek_enabled)
+        RequestStore.store[:peek_enabled]
+      else
+        RequestStore.store[:peek_enabled] = cookies[:perf_bar_enabled].present?
+      end
+    end
+  end
+
   protected
 
   # This filter handles both private tokens and personal access tokens
diff --git a/app/views/help/_shortcuts.html.haml b/app/views/help/_shortcuts.html.haml
index ea8bbe92d865b20a8b5df29d1c103b426ccbaf64..420172289080a40e420ccecebdb8a32129536f05 100644
--- a/app/views/help/_shortcuts.html.haml
+++ b/app/views/help/_shortcuts.html.haml
@@ -27,6 +27,10 @@
                   %td.shortcut
                     .key f
                   %td Focus Filter
+                %tr
+                  %td.shortcut
+                    .key p b
+                  %td Enable the Performance Bar
                 %tr
                   %td.shortcut
                     .key ?
diff --git a/app/views/layouts/_head.html.haml b/app/views/layouts/_head.html.haml
index 1ef0d524dbb6908e6844ae1370b75be4039ab19a..eea33b5966f729bb3a81924f76596f24f1227511 100644
--- a/app/views/layouts/_head.html.haml
+++ b/app/views/layouts/_head.html.haml
@@ -28,6 +28,7 @@
   = stylesheet_link_tag "application", media: "all"
   = stylesheet_link_tag "print",       media: "print"
   = stylesheet_link_tag "test",        media: "all" if Rails.env.test?
+  = stylesheet_link_tag 'peek' if peek_enabled?
 
   = Gon::Base.render_data
 
@@ -37,6 +38,7 @@
   = webpack_bundle_tag "main"
   = webpack_bundle_tag "raven" if current_application_settings.clientside_sentry_enabled
   = webpack_bundle_tag "test" if Rails.env.test?
+  = webpack_bundle_tag 'peek' if peek_enabled?
 
   - if content_for?(:page_specific_javascripts)
     = yield :page_specific_javascripts
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 03688e9ff21dff600e7c31490d043bffaf08066d..2b07273a0a84debea7f08db8b7df92da2355ce0e 100644
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -3,6 +3,7 @@
   = render "layouts/head"
   %body{ class: @body_class, data: { page: body_data_page, project: "#{@project.path if @project}", group: "#{@group.path if @group}" } }
     = render "layouts/init_auto_complete" if @gfm_form
+    = render 'peek/bar'
     = render "layouts/header/default", title: header_title
     = render 'layouts/page', sidebar: sidebar, nav: nav
 
diff --git a/config/application.rb b/config/application.rb
index b0533759252e565833fa0f9ec657fb3733ebf1d6..8bbecf3ed0f5287cd2b45e62406b5ea7f27a6526 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -105,6 +105,7 @@ module Gitlab
     config.assets.precompile << "katex.css"
     config.assets.precompile << "katex.js"
     config.assets.precompile << "xterm/xterm.css"
+    config.assets.precompile << "peek.css"
     config.assets.precompile << "lib/ace.js"
     config.assets.precompile << "vendor/assets/fonts/*"
     config.assets.precompile << "test.css"
diff --git a/config/initializers/peek.rb b/config/initializers/peek.rb
new file mode 100644
index 0000000000000000000000000000000000000000..73da7be788943b0c7a0ec89ed698955af5105493
--- /dev/null
+++ b/config/initializers/peek.rb
@@ -0,0 +1,9 @@
+Rails.application.config.peek.adapter = :redis, { client: ::Redis.new(Gitlab::Redis.params) }
+
+Peek.into Peek::Views::Host
+Peek.into Peek::Views::PerformanceBar
+Peek.into Gitlab::Database.mysql? ? Peek::Views::Mysql2 : Peek::Views::PG
+Peek.into Peek::Views::Redis
+Peek.into Peek::Views::Sidekiq
+Peek.into Peek::Views::Rblineprof
+Peek.into Peek::Views::GC
diff --git a/config/routes.rb b/config/routes.rb
index d909be38b42c441f7c5d291622ff53df01f39523..9a117711083467948f8567f8fc47227a33a09aaf 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -11,6 +11,7 @@ Rails.application.routes.draw do
     post :toggle_award_emoji, on: :member
   end
 
+  mount Peek::Railtie => '/peek'
   draw :sherlock
   draw :development
   draw :ci
diff --git a/config/webpack.config.js b/config/webpack.config.js
index 7501acb763384fc676367d1eade4926beaf232bd..bb77c12f88a2c2d20545b831c3287ccef285109f 100644
--- a/config/webpack.config.js
+++ b/config/webpack.config.js
@@ -68,6 +68,7 @@ var config = {
     raven:                './raven/index.js',
     vue_merge_request_widget: './vue_merge_request_widget/index.js',
     test:                 './test.js',
+    peek:                 './peek.js',
   },
 
   output: {
diff --git a/lib/gitlab/performance_bar.rb b/lib/gitlab/performance_bar.rb
new file mode 100644
index 0000000000000000000000000000000000000000..3324fec94d4c42ed47ef6c0b93dfdca38b8f7d7a
--- /dev/null
+++ b/lib/gitlab/performance_bar.rb
@@ -0,0 +1,7 @@
+module Gitlab
+  module PerformanceBar
+    def self.enabled?
+      ENV["PERFORMANCE_BAR"] == '1'
+    end
+  end
+end
diff --git a/vendor/assets/javascripts/jquery.tipsy.js b/vendor/assets/javascripts/jquery.tipsy.js
new file mode 100644
index 0000000000000000000000000000000000000000..d9fced24b609df9bbbe8e2fbc039fcdde83619e6
--- /dev/null
+++ b/vendor/assets/javascripts/jquery.tipsy.js
@@ -0,0 +1,258 @@
+// tipsy, facebook style tooltips for jquery
+// version 1.0.0a
+// (c) 2008-2010 jason frame [jason@onehackoranother.com]
+// released under the MIT license
+
+(function($) {
+
+    function maybeCall(thing, ctx) {
+        return (typeof thing == 'function') ? (thing.call(ctx)) : thing;
+    };
+
+    function isElementInDOM(ele) {
+      while (ele = ele.parentNode) {
+        if (ele == document) return true;
+      }
+      return false;
+    };
+
+    function Tipsy(element, options) {
+        this.$element = $(element);
+        this.options = options;
+        this.enabled = true;
+        this.fixTitle();
+    };
+
+    Tipsy.prototype = {
+        show: function() {
+            var title = this.getTitle();
+            if (title && this.enabled) {
+                var $tip = this.tip();
+
+                $tip.find('.tipsy-inner')[this.options.html ? 'html' : 'text'](title);
+                $tip[0].className = 'tipsy'; // reset classname in case of dynamic gravity
+                $tip.remove().css({top: 0, left: 0, visibility: 'hidden', display: 'block'}).prependTo(document.body);
+
+                var pos = $.extend({}, this.$element.offset(), {
+                    width: this.$element[0].offsetWidth,
+                    height: this.$element[0].offsetHeight
+                });
+
+                var actualWidth = $tip[0].offsetWidth,
+                    actualHeight = $tip[0].offsetHeight,
+                    gravity = maybeCall(this.options.gravity, this.$element[0]);
+
+                var tp;
+                switch (gravity.charAt(0)) {
+                    case 'n':
+                        tp = {top: pos.top + pos.height + this.options.offset, left: pos.left + pos.width / 2 - actualWidth / 2};
+                        break;
+                    case 's':
+                        tp = {top: pos.top - actualHeight - this.options.offset, left: pos.left + pos.width / 2 - actualWidth / 2};
+                        break;
+                    case 'e':
+                        tp = {top: pos.top + pos.height / 2 - actualHeight / 2, left: pos.left - actualWidth - this.options.offset};
+                        break;
+                    case 'w':
+                        tp = {top: pos.top + pos.height / 2 - actualHeight / 2, left: pos.left + pos.width + this.options.offset};
+                        break;
+                }
+
+                if (gravity.length == 2) {
+                    if (gravity.charAt(1) == 'w') {
+                        tp.left = pos.left + pos.width / 2 - 15;
+                    } else {
+                        tp.left = pos.left + pos.width / 2 - actualWidth + 15;
+                    }
+                }
+
+                $tip.css(tp).addClass('tipsy-' + gravity);
+                $tip.find('.tipsy-arrow')[0].className = 'tipsy-arrow tipsy-arrow-' + gravity.charAt(0);
+                if (this.options.className) {
+                    $tip.addClass(maybeCall(this.options.className, this.$element[0]));
+                }
+
+                if (this.options.fade) {
+                    $tip.stop().css({opacity: 0, display: 'block', visibility: 'visible'}).animate({opacity: this.options.opacity});
+                } else {
+                    $tip.css({visibility: 'visible', opacity: this.options.opacity});
+                }
+            }
+        },
+
+        hide: function() {
+            if (this.options.fade) {
+                this.tip().stop().fadeOut(function() { $(this).remove(); });
+            } else {
+                this.tip().remove();
+            }
+        },
+
+        fixTitle: function() {
+            var $e = this.$element;
+            if ($e.attr('title') || typeof($e.attr('original-title')) != 'string') {
+                $e.attr('original-title', $e.attr('title') || '').removeAttr('title');
+            }
+        },
+
+        getTitle: function() {
+            var title, $e = this.$element, o = this.options;
+            this.fixTitle();
+            var title, o = this.options;
+            if (typeof o.title == 'string') {
+                title = $e.attr(o.title == 'title' ? 'original-title' : o.title);
+            } else if (typeof o.title == 'function') {
+                title = o.title.call($e[0]);
+            }
+            title = ('' + title).replace(/(^\s*|\s*$)/, "");
+            return title || o.fallback;
+        },
+
+        tip: function() {
+            if (!this.$tip) {
+                this.$tip = $('<div class="tipsy"></div>').html('<div class="tipsy-arrow"></div><div class="tipsy-inner"></div>');
+                this.$tip.data('tipsy-pointee', this.$element[0]);
+            }
+            return this.$tip;
+        },
+
+        validate: function() {
+            if (!this.$element[0].parentNode) {
+                this.hide();
+                this.$element = null;
+                this.options = null;
+            }
+        },
+
+        enable: function() { this.enabled = true; },
+        disable: function() { this.enabled = false; },
+        toggleEnabled: function() { this.enabled = !this.enabled; }
+    };
+
+    $.fn.tipsy = function(options) {
+
+        if (options === true) {
+            return this.data('tipsy');
+        } else if (typeof options == 'string') {
+            var tipsy = this.data('tipsy');
+            if (tipsy) tipsy[options]();
+            return this;
+        }
+
+        options = $.extend({}, $.fn.tipsy.defaults, options);
+
+        function get(ele) {
+            var tipsy = $.data(ele, 'tipsy');
+            if (!tipsy) {
+                tipsy = new Tipsy(ele, $.fn.tipsy.elementOptions(ele, options));
+                $.data(ele, 'tipsy', tipsy);
+            }
+            return tipsy;
+        }
+
+        function enter() {
+            var tipsy = get(this);
+            tipsy.hoverState = 'in';
+            if (options.delayIn == 0) {
+                tipsy.show();
+            } else {
+                tipsy.fixTitle();
+                setTimeout(function() { if (tipsy.hoverState == 'in') tipsy.show(); }, options.delayIn);
+            }
+        };
+
+        function leave() {
+            var tipsy = get(this);
+            tipsy.hoverState = 'out';
+            if (options.delayOut == 0) {
+                tipsy.hide();
+            } else {
+                setTimeout(function() { if (tipsy.hoverState == 'out') tipsy.hide(); }, options.delayOut);
+            }
+        };
+
+        if (!options.live) this.each(function() { get(this); });
+
+        if (options.trigger != 'manual') {
+            var binder   = options.live ? 'live' : 'bind',
+                eventIn  = options.trigger == 'hover' ? 'mouseenter' : 'focus',
+                eventOut = options.trigger == 'hover' ? 'mouseleave' : 'blur';
+            this[binder](eventIn, enter)[binder](eventOut, leave);
+        }
+
+        return this;
+
+    };
+
+    $.fn.tipsy.defaults = {
+        className: null,
+        delayIn: 0,
+        delayOut: 0,
+        fade: false,
+        fallback: '',
+        gravity: 'n',
+        html: false,
+        live: false,
+        offset: 0,
+        opacity: 0.8,
+        title: 'title',
+        trigger: 'hover'
+    };
+
+    $.fn.tipsy.revalidate = function() {
+      $('.tipsy').each(function() {
+        var pointee = $.data(this, 'tipsy-pointee');
+        if (!pointee || !isElementInDOM(pointee)) {
+          $(this).remove();
+        }
+      });
+    };
+
+    // Overwrite this method to provide options on a per-element basis.
+    // For example, you could store the gravity in a 'tipsy-gravity' attribute:
+    // return $.extend({}, options, {gravity: $(ele).attr('tipsy-gravity') || 'n' });
+    // (remember - do not modify 'options' in place!)
+    $.fn.tipsy.elementOptions = function(ele, options) {
+        return $.metadata ? $.extend({}, options, $(ele).metadata()) : options;
+    };
+
+    $.fn.tipsy.autoNS = function() {
+        return $(this).offset().top > ($(document).scrollTop() + $(window).height() / 2) ? 's' : 'n';
+    };
+
+    $.fn.tipsy.autoWE = function() {
+        return $(this).offset().left > ($(document).scrollLeft() + $(window).width() / 2) ? 'e' : 'w';
+    };
+
+    /**
+     * yields a closure of the supplied parameters, producing a function that takes
+     * no arguments and is suitable for use as an autogravity function like so:
+     *
+     * @param margin (int) - distance from the viewable region edge that an
+     *        element should be before setting its tooltip's gravity to be away
+     *        from that edge.
+     * @param prefer (string, e.g. 'n', 'sw', 'w') - the direction to prefer
+     *        if there are no viewable region edges effecting the tooltip's
+     *        gravity. It will try to vary from this minimally, for example,
+     *        if 'sw' is preferred and an element is near the right viewable
+     *        region edge, but not the top edge, it will set the gravity for
+     *        that element's tooltip to be 'se', preserving the southern
+     *        component.
+     */
+     $.fn.tipsy.autoBounds = function(margin, prefer) {
+    return function() {
+      var dir = {ns: prefer[0], ew: (prefer.length > 1 ? prefer[1] : false)},
+          boundTop = $(document).scrollTop() + margin,
+          boundLeft = $(document).scrollLeft() + margin,
+          $this = $(this);
+
+      if ($this.offset().top < boundTop) dir.ns = 'n';
+      if ($this.offset().left < boundLeft) dir.ew = 'w';
+      if ($(window).width() + $(document).scrollLeft() - $this.offset().left < margin) dir.ew = 'e';
+      if ($(window).height() + $(document).scrollTop() - $this.offset().top < margin) dir.ns = 's';
+
+      return dir.ns + (dir.ew ? dir.ew : '');
+    }
+  };
+
+})(jQuery);
diff --git a/vendor/assets/javascripts/peek.js b/vendor/assets/javascripts/peek.js
new file mode 100644
index 0000000000000000000000000000000000000000..2d5d05ca8e64a44693b84e634d096d519efecea9
--- /dev/null
+++ b/vendor/assets/javascripts/peek.js
@@ -0,0 +1,84 @@
+var requestId;
+
+requestId = null;
+
+(function($) {
+  var fetchRequestResults, getRequestId, initializeTipsy, peekEnabled, toggleBar, updatePerformanceBar;
+  getRequestId = function() {
+    if (requestId != null) {
+      return requestId;
+    } else {
+      return $('#peek').data('request-id');
+    }
+  };
+  peekEnabled = function() {
+    return $('#peek').length;
+  };
+  updatePerformanceBar = function(results) {
+    var key, label;
+    for (key in results.data) {
+      for (label in results.data[key]) {
+        $("[data-defer-to=" + key + "-" + label + "]").text(results.data[key][label]);
+      }
+    }
+    return $(document).trigger('peek:render', [getRequestId(), results]);
+  };
+  initializeTipsy = function() {
+    return $('#peek .peek-tooltip, #peek .tooltip').each(function() {
+      var el, gravity;
+      el = $(this);
+      gravity = el.hasClass('rightwards') || el.hasClass('leftwards') ? $.fn.tipsy.autoWE : $.fn.tipsy.autoNS;
+      return el.tipsy({
+        gravity: gravity
+      });
+    });
+  };
+  toggleBar = function(event) {
+    var wrapper;
+    if ($(event.target).is(':input')) {
+      return;
+    }
+    if (event.which === 96 && !event.metaKey) {
+      wrapper = $('#peek');
+      if (wrapper.hasClass('disabled')) {
+        wrapper.removeClass('disabled');
+        return document.cookie = "peek=true; path=/";
+      } else {
+        wrapper.addClass('disabled');
+        return document.cookie = "peek=false; path=/";
+      }
+    }
+  };
+  fetchRequestResults = function() {
+    return $.ajax('/peek/results', {
+      data: {
+        request_id: getRequestId()
+      },
+      success: function(data, textStatus, xhr) {
+        return updatePerformanceBar(data);
+      },
+      error: function(xhr, textStatus, error) {}
+    });
+  };
+  $(document).on('keypress', toggleBar);
+  $(document).on('peek:update', initializeTipsy);
+  $(document).on('peek:update', fetchRequestResults);
+  $(document).on('pjax:end', function(event, xhr, options) {
+    if (xhr != null) {
+      requestId = xhr.getResponseHeader('X-Request-Id');
+    }
+    if (peekEnabled()) {
+      return $(this).trigger('peek:update');
+    }
+  });
+  $(document).on('page:change turbolinks:load', function() {
+    if (peekEnabled()) {
+      return $(this).trigger('peek:update');
+    }
+  });
+  return $(function() {
+    if (peekEnabled()) {
+      return $(this).trigger('peek:update');
+    }
+  });
+})(jQuery);
diff --git a/vendor/assets/javascripts/peek.performance_bar.js b/vendor/assets/javascripts/peek.performance_bar.js
new file mode 100644
index 0000000000000000000000000000000000000000..3318e21889003161ffa844195ddb5183737d43d2
--- /dev/null
+++ b/vendor/assets/javascripts/peek.performance_bar.js
@@ -0,0 +1,191 @@
+var PerformanceBar, ajaxStart, renderPerformanceBar, updateStatus;
+
+PerformanceBar = (function() {
+  PerformanceBar.prototype.appInfo = null;
+
+  PerformanceBar.prototype.width = null;
+
+  PerformanceBar.formatTime = function(value) {
+    if (value >= 1000) {
+      return ((value / 1000).toFixed(3)) + "s";
+    } else {
+      return (value.toFixed(0)) + "ms";
+    }
+  };
+
+  function PerformanceBar(options) {
+    var k, v;
+    if (options == null) {
+      options = {};
+    }
+    this.el = $('#peek-view-performance-bar .performance-bar');
+    for (k in options) {
+      v = options[k];
+      this[k] = v;
+    }
+    if (this.width == null) {
+      this.width = this.el.width();
+    }
+    if (this.timing == null) {
+      this.timing = window.performance.timing;
+    }
+  }
+
+  PerformanceBar.prototype.render = function(serverTime) {
+    var networkTime, perfNetworkTime;
+    if (serverTime == null) {
+      serverTime = 0;
+    }
+    this.el.empty();
+    this.addBar('frontend', '#90d35b', 'domLoading', 'domInteractive');
+    perfNetworkTime = this.timing.responseEnd - this.timing.requestStart;
+    if (serverTime && serverTime <= perfNetworkTime) {
+      networkTime = perfNetworkTime - serverTime;
+      this.addBar('latency / receiving', '#f1faff', this.timing.requestStart + serverTime, this.timing.requestStart + serverTime + networkTime);
+      this.addBar('app', '#90afcf', this.timing.requestStart, this.timing.requestStart + serverTime, this.appInfo);
+    } else {
+      this.addBar('backend', '#c1d7ee', 'requestStart', 'responseEnd');
+    }
+    this.addBar('tcp / ssl', '#45688e', 'connectStart', 'connectEnd');
+    this.addBar('redirect', '#0c365e', 'redirectStart', 'redirectEnd');
+    this.addBar('dns', '#082541', 'domainLookupStart', 'domainLookupEnd');
+    return this.el;
+  };
+
+  PerformanceBar.prototype.isLoaded = function() {
+    return this.timing.domInteractive;
+  };
+
+  PerformanceBar.prototype.start = function() {
+    return this.timing.navigationStart;
+  };
+
+  PerformanceBar.prototype.end = function() {
+    return this.timing.domInteractive;
+  };
+
+  PerformanceBar.prototype.total = function() {
+    return this.end() - this.start();
+  };
+
+  PerformanceBar.prototype.addBar = function(name, color, start, end, info) {
+    var bar, left, offset, time, title, width;
+    if (typeof start === 'string') {
+      start = this.timing[start];
+    }
+    if (typeof end === 'string') {
+      end = this.timing[end];
+    }
+    if (!((start != null) && (end != null))) {
+      return;
+    }
+    time = end - start;
+    offset = start - this.start();
+    left = this.mapH(offset);
+    width = this.mapH(time);
+    title = name + ": " + (PerformanceBar.formatTime(time));
+    bar = $('<li></li>', {
+      title: title,
+      "class": 'peek-tooltip'
+    });
+    bar.css({
+      width: width + "px",
+      left: left + "px",
+      background: color
+    });
+    bar.tipsy({
+      gravity: $.fn.tipsy.autoNS
+    });
+    return this.el.append(bar);
+  };
+
+  PerformanceBar.prototype.mapH = function(offset) {
+    return offset * (this.width / this.total());
+  };
+
+  return PerformanceBar;
+
+})();
+
+renderPerformanceBar = function() {
+  var bar, resp, span, time;
+  resp = $('#peek-server_response_time');
+  time = Math.round(resp.data('time') * 1000);
+  bar = new PerformanceBar;
+  bar.render(time);
+  span = $('<span>', {
+    'class': 'peek-tooltip',
+    title: 'Total navigation time for this page.'
+  }).text(PerformanceBar.formatTime(bar.total()));
+  span.tipsy({
+    gravity: $.fn.tipsy.autoNS
+  });
+  return updateStatus(span);
+};
+
+updateStatus = function(html) {
+  return $('#serverstats').html(html);
+};
+
+ajaxStart = null;
+
+$(document).on('pjax:start page:fetch turbolinks:request-start', function(event) {
+  return ajaxStart = event.timeStamp;
+});
+
+$(document).on('pjax:end page:load turbolinks:load', function(event, xhr) {
+  var ajaxEnd, serverTime, total;
+  if (ajaxStart == null) {
+    return;
+  }
+  ajaxEnd = event.timeStamp;
+  total = ajaxEnd - ajaxStart;
+  serverTime = xhr ? parseInt(xhr.getResponseHeader('X-Runtime')) : 0;
+  return setTimeout(function() {
+    var bar, now, span, tech;
+    now = new Date().getTime();
+    bar = new PerformanceBar({
+      timing: {
+        requestStart: ajaxStart,
+        responseEnd: ajaxEnd,
+        domLoading: ajaxEnd,
+        domInteractive: now
+      },
+      isLoaded: function() {
+        return true;
+      },
+      start: function() {
+        return ajaxStart;
+      },
+      end: function() {
+        return now;
+      }
+    });
+    bar.render(serverTime);
+    if ($.fn.pjax != null) {
+      tech = 'PJAX';
+    } else {
+      tech = 'Turbolinks';
+    }
+    span = $('<span>', {
+      'class': 'peek-tooltip',
+      title: tech + " navigation time"
+    }).text(PerformanceBar.formatTime(total));
+    span.tipsy({
+      gravity: $.fn.tipsy.autoNS
+    });
+    updateStatus(span);
+    return ajaxStart = null;
+  }, 0);
+});
+
+$(function() {
+  if (window.performance) {
+    return renderPerformanceBar();
+  } else {
+    return $('#peek-view-performance-bar').remove();
+  }
+});
+
+// ---
+// generated by coffee-script 1.9.2
diff --git a/vendor/assets/javascripts/peek.rblineprof.js b/vendor/assets/javascripts/peek.rblineprof.js
new file mode 100644
index 0000000000000000000000000000000000000000..cad6e24d40ee7fd3d41a2c9b00dba1f38d5cf4e9
--- /dev/null
+++ b/vendor/assets/javascripts/peek.rblineprof.js
@@ -0,0 +1,5 @@
+$(document).on('click', '.js-lineprof-file', function(e) {
+  $(this).parents('.heading').next('div').toggle();
+  e.preventDefault();
+  return false;
+});
diff --git a/vendor/assets/stylesheets/peek.scss b/vendor/assets/stylesheets/peek.scss
new file mode 100644
index 0000000000000000000000000000000000000000..4b2957c557502dfe75937f6a51d32854407a93b3
--- /dev/null
+++ b/vendor/assets/stylesheets/peek.scss
@@ -0,0 +1,138 @@
+//= require peek/views/performance_bar
+//= require peek/views/rblineprof
+//= require peek/views/rblineprof/pygments
+
+#peek {
+  background: #000;
+  height: 35px;
+  line-height: 35px;
+  color: #999;
+  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.75);
+
+  .hidden {
+    display: none;
+    visibility: visible;
+  }
+
+  &.disabled {
+    display: none;
+  }
+
+  &.production {
+    background-color: #222;
+  }
+
+  &.staging {
+    background-color: #291430;
+  }
+
+  &.development {
+    background-color: #4c1210;
+  }
+
+  .wrapper {
+    width: 800px;
+    margin: 0 auto;
+  }
+
+  // UI Elements
+  .bucket {
+    background: #111;
+    display: inline-block;
+    padding: 4px 6px;
+    font-family: Consolas, "Liberation Mono", Courier, monospace;
+    line-height: 1;
+    color: #ccc;
+    border-radius: 3px;
+    box-shadow: 0 1px 0 rgba(255,255,255,.2), inset 0 1px 2px rgba(0,0,0,.25);
+
+    .hidden {
+      display: none;
+    }
+
+    &:hover .hidden {
+      display: inline;
+    }
+  }
+
+  strong {
+    color: #fff;
+  }
+
+  .view {
+    margin-right: 15px;
+    float: left;
+
+    &:last-child {
+      margin-right: 0;
+    }
+  }
+
+  .css-truncate {
+    &.css-truncate-target,
+    .css-truncate-target {
+      display: inline-block;
+      max-width: 125px;
+      overflow: hidden;
+      text-overflow: ellipsis;
+      white-space: nowrap;
+      vertical-align: top;
+    }
+
+    &.expandable:hover .css-truncate-target,
+    &.expandable:hover.css-truncate-target {
+      max-width: 10000px !important;
+    }
+  }
+}
+
+// .performance-bar {
+//   position: relative;
+//   top: 2px;
+//   display: inline-block;
+//   width: 75px;
+//   height: 10px;
+//   margin: 0 0 0 5px;
+//   list-style: none;
+//   background-color: rgba(0, 0, 0, .5);
+//   border: 1px solid rgba(0, 0, 0, .7);
+//   border-radius: 2px;
+//   box-shadow: 0 1px 0 rgba(255, 255, 255, .15);
+//
+//   li {
+//     position: absolute;
+//     top: 0;
+//     bottom: 0;
+//     overflow: hidden;
+//     opacity: .8;
+//     color: transparent;
+//
+//     &:hover {
+//       opacity: 1;
+//       cursor: default;
+//     }
+//   }
+// }
+
+.tipsy { font-size: 10px; position: absolute; padding: 5px; z-index: 100000; }
+  .tipsy-inner { background-color: #000; color: #FFF; max-width: 200px; padding: 5px 8px 4px 8px; text-align: center; }
+
+  /* Rounded corners */
+  .tipsy-inner { border-radius: 3px; -moz-border-radius: 3px; -webkit-border-radius: 3px; }
+
+  .tipsy-arrow { position: absolute; width: 0; height: 0; line-height: 0; border: 5px dashed #000; }
+
+  /* Rules to colour arrows */
+  .tipsy-arrow-n { border-bottom-color: #000; }
+  .tipsy-arrow-s { border-top-color: #000; }
+  .tipsy-arrow-e { border-left-color: #000; }
+  .tipsy-arrow-w { border-right-color: #000; }
+
+  .tipsy-n .tipsy-arrow { top: 0px; left: 50%; margin-left: -5px; border-bottom-style: solid; border-top: none; border-left-color: transparent; border-right-color: transparent; }
+    .tipsy-nw .tipsy-arrow { top: 0; left: 10px; border-bottom-style: solid; border-top: none; border-left-color: transparent; border-right-color: transparent;}
+    .tipsy-ne .tipsy-arrow { top: 0; right: 10px; border-bottom-style: solid; border-top: none;  border-left-color: transparent; border-right-color: transparent;}
+  .tipsy-s .tipsy-arrow { bottom: 0; left: 50%; margin-left: -5px; border-top-style: solid; border-bottom: none;  border-left-color: transparent; border-right-color: transparent; }
+    .tipsy-sw .tipsy-arrow { bottom: 0; left: 10px; border-top-style: solid; border-bottom: none;  border-left-color: transparent; border-right-color: transparent; }
+    .tipsy-se .tipsy-arrow { bottom: 0; right: 10px; border-top-style: solid; border-bottom: none; border-left-color: transparent; border-right-color: transparent; }
+  .tipsy-e .tipsy-arrow { right: 0; top: 50%; margin-top: -5px; border-left-style: solid; border-right: none; border-top-color: transparent; border-bottom-color: transparent; }
+  .tipsy-w .tipsy-arrow { left: 0; top: 50%; margin-top: -5px; border-right-style: solid; border-left: none; border-top-color: transparent; border-bottom-color: transparent; }