diff --git a/CHANGELOG b/CHANGELOG
index 792ec4fbe29e18d3dc85c58d708b5409db03dfb6..d2704ed204edcb464da72da243f1e013ca1560b7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.1.0 (unreleased)
   - Fix error preventing displaying of commit data for a directory with a leading dot (Stan Hu)
+  - Speed up load times of issue detail pages by roughly 1.5x
   - Make diff file view easier to use on mobile screens (Stan Hu)
   - Add support for creating directories from Files page (Stan Hu)
   - Allow removing of project without confirmation when JavaScript is disabled (Stan Hu)
diff --git a/Gemfile b/Gemfile
index 29d9db05f42a36c9d531ebdddb279c2515b9dc32..4fbd37f6c8bd4b06503c3e4d0f5ed6959e231ef7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -216,6 +216,9 @@ group :development do
   gem 'quiet_assets', '~> 1.0.2'
   gem 'rack-mini-profiler', '~> 0.9.0', require: false
   gem 'rerun', '~> 0.10.0'
+  gem 'bullet', require: false
+  gem 'active_record_query_trace', require: false
+  gem 'rack-lineprof', platform: :mri
 
   # Better errors handler
   gem 'better_errors', '~> 1.0.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index ee545f366f42919b7abef66413884f617c75d8ec..b92d9766d3a808c8abf840d21cf694ed144c22da 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -17,6 +17,7 @@ GEM
       activesupport (= 4.1.12)
       builder (~> 3.1)
       erubis (~> 2.7.0)
+    active_record_query_trace (1.5)
     activemodel (4.1.12)
       activesupport (= 4.1.12)
       builder (~> 3.1)
@@ -87,6 +88,9 @@ GEM
       terminal-table (~> 1.4)
     browser (1.0.0)
     builder (3.2.2)
+    bullet (4.14.9)
+      activesupport (>= 3.0.0)
+      uniform_notifier (~> 1.9.0)
     byebug (6.0.2)
     cal-heatmap-rails (0.0.1)
     capybara (2.4.4)
@@ -134,6 +138,7 @@ GEM
     daemons (1.2.3)
     database_cleaner (1.4.1)
     debug_inspector (0.0.2)
+    debugger-ruby_core_source (1.3.8)
     default_value_for (3.0.1)
       activerecord (>= 3.2.0, < 5.0)
     descendants_tracker (0.0.4)
@@ -484,6 +489,10 @@ GEM
     rack-attack (4.3.0)
       rack
     rack-cors (0.4.0)
+    rack-lineprof (0.0.3)
+      rack (~> 1.5)
+      rblineprof (~> 0.3.6)
+      term-ansicolor (~> 1.3)
     rack-mini-profiler (0.9.7)
       rack (>= 1.1.3)
     rack-mount (0.8.3)
@@ -522,6 +531,8 @@ GEM
     rb-fsevent (0.9.5)
     rb-inotify (0.9.5)
       ffi (>= 0.5.0)
+    rblineprof (0.3.6)
+      debugger-ruby_core_source (~> 1.3)
     rbvmomi (1.8.2)
       builder
       nokogiri (>= 1.4.1)
@@ -736,6 +747,7 @@ GEM
     unicorn-worker-killer (0.4.3)
       get_process_mem (~> 0)
       unicorn (~> 4)
+    uniform_notifier (1.9.0)
     uuid (2.3.8)
       macaddr (~> 1.0)
     version_sorter (2.0.0)
@@ -765,6 +777,7 @@ PLATFORMS
 DEPENDENCIES
   RedCloth (~> 4.2.9)
   ace-rails-ap (~> 2.0.1)
+  active_record_query_trace
   activerecord-deprecated_finders (~> 1.0.3)
   activerecord-session_store (~> 0.1.0)
   acts-as-taggable-on (~> 3.4)
@@ -781,6 +794,7 @@ DEPENDENCIES
   bootstrap-sass (~> 3.0)
   brakeman (= 3.0.1)
   browser (~> 1.0.0)
+  bullet
   byebug
   cal-heatmap-rails (~> 0.0.1)
   capybara (~> 2.4.0)
@@ -861,6 +875,7 @@ DEPENDENCIES
   quiet_assets (~> 1.0.2)
   rack-attack (~> 4.3.0)
   rack-cors (~> 0.4.0)
+  rack-lineprof
   rack-mini-profiler (~> 0.9.0)
   rack-oauth2 (~> 1.0.5)
   rails (= 4.1.12)
diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index 4612abcbae8f75c528e5f289007c1a75b5e6e8ca..97485c101fb39433039a5d18266874c5b87f1d1e 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -57,7 +57,7 @@ class Projects::IssuesController < Projects::ApplicationController
   def show
     @participants = @issue.participants(current_user)
     @note = @project.notes.new(noteable: @issue)
-    @notes = @issue.notes.inc_author.fresh
+    @notes = @issue.notes.with_associations.fresh
     @noteable = @issue
 
     respond_with(@issue)
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index cab2278adb7f8fe3c072d378021566082f9c1d42..8ecdeaf8e76ba8fe241838106c6ed9bc9509579c 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -68,13 +68,17 @@ module ApplicationHelper
     end
   end
 
-  def avatar_icon(user_email = '', size = nil)
-    user = User.find_by(email: user_email)
+  def avatar_icon(user_or_email = nil, size = nil)
+    if user_or_email.is_a?(User)
+      user = user_or_email
+    else
+      user = User.find_by(email: user_or_email)
+    end
 
     if user
       user.avatar_url(size) || default_avatar
     else
-      gravatar_icon(user_email, size)
+      gravatar_icon(user_or_email, size)
     end
   end
 
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index b7965aee8750f40bcc964fc3ba8e2dd53cd6e779..dbadbb745492d878bc2b4478079ab7c69adf3265 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -29,7 +29,7 @@ module ProjectsHelper
     author_html =  ""
 
     # Build avatar image tag
-    author_html << image_tag(avatar_icon(author.try(:email), opts[:size]), width: opts[:size], class: "avatar avatar-inline #{"s#{opts[:size]}" if opts[:size]}", alt:'') if opts[:avatar]
+    author_html << image_tag(avatar_icon(author, opts[:size]), width: opts[:size], class: "avatar avatar-inline #{"s#{opts[:size]}" if opts[:size]}", alt:'') if opts[:avatar]
 
     # Build name span tag
     author_html << content_tag(:span, sanitize(author.name), class: opts[:author_class]) if opts[:name]
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index 4db4ffb2e79835fb234e53470f32da2c105fad6a..0e8bcc1a4ece30b363b26d6c05db5396ff6d5026 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -47,7 +47,8 @@ module Issuable
              prefix: true
 
     attr_mentionable :title, :description
-    participant :author, :assignee, :notes, :mentioned_users
+
+    participant :author, :assignee, :notes_with_associations, :mentioned_users
   end
 
   module ClassMethods
@@ -176,6 +177,10 @@ module Issuable
     self.class.to_s.underscore
   end
 
+  def notes_with_associations
+    notes.includes(:author, :project)
+  end
+
   private
 
   def filter_superceded_votes(votes, notes)
diff --git a/app/models/group.rb b/app/models/group.rb
index 9cd146bb73bf18e718beab0f34594b7ca7a50c8c..465c22d23ac85ae8305112bf9f637fac3693f336 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -64,7 +64,7 @@ class Group < Namespace
   end
 
   def owners
-    @owners ||= group_members.owners.map(&:user)
+    @owners ||= group_members.owners.includes(:user).map(&:user)
   end
 
   def add_users(user_ids, access_level, current_user = nil)
diff --git a/app/models/note.rb b/app/models/note.rb
index ee0c14598f3aca97b1a9aaecce0922fc8d7e202e..ebbdd2f33a127eebe57db56ab8743c927cd84bd2 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -60,6 +60,11 @@ class Note < ActiveRecord::Base
   scope :inc_author_project, ->{ includes(:project, :author) }
   scope :inc_author, ->{ includes(:author) }
 
+  scope :with_associations, -> do
+    includes(:author, :noteable, :updated_by,
+             project: [:project_members, { group: [:group_members] }])
+  end
+
   serialize :st_diff
   before_create :set_diff, if: ->(n) { n.line_code.present? }
 
diff --git a/app/models/project_team.rb b/app/models/project_team.rb
index f602a965364e6e1584e689d35b7f734b07575e14..9f380a382cb40f0acaf855d659ebd034903b26a2 100644
--- a/app/models/project_team.rb
+++ b/app/models/project_team.rb
@@ -139,15 +139,28 @@ class ProjectTeam
     Gitlab::Access.options.key max_member_access(user_id)
   end
 
+  # This method assumes project and group members are eager loaded for optimal
+  # performance.
   def max_member_access(user_id)
     access = []
-    access << project.project_members.find_by(user_id: user_id).try(:access_field)
+
+    project.project_members.each do |member|
+      if member.user_id == user_id
+        access << member.access_field if member.access_field
+        break
+      end
+    end
 
     if group
-      access << group.group_members.find_by(user_id: user_id).try(:access_field)
+      group.group_members.each do |member|
+        if member.user_id == user_id
+          access << member.access_field if member.access_field
+          break
+        end
+      end
     end
 
-    access.compact.max
+    access.max
   end
 
   private
diff --git a/app/views/admin/users/show.html.haml b/app/views/admin/users/show.html.haml
index a383ea573841a5fbcfc9f8fa2d4038f4b2c7ecda..231bcb0426f0a3f1ff5b0e2c4e302e611de72906 100644
--- a/app/views/admin/users/show.html.haml
+++ b/app/views/admin/users/show.html.haml
@@ -8,7 +8,7 @@
         = @user.name
       %ul.well-list
         %li
-          = image_tag avatar_icon(@user.email, 60), class: "avatar s60"
+          = image_tag avatar_icon(@user, 60), class: "avatar s60"
         %li
           %span.light Profile page:
           %strong
diff --git a/app/views/dashboard/milestones/_issue.html.haml b/app/views/dashboard/milestones/_issue.html.haml
index f689b9698eb76806e1f50a6fdaa1e1eb9e9058bd..1408ebdd5dcf6953a63ae06a96ab531118871524 100644
--- a/app/views/dashboard/milestones/_issue.html.haml
+++ b/app/views/dashboard/milestones/_issue.html.haml
@@ -7,4 +7,4 @@
     = link_to_gfm issue.title, [project.namespace.becomes(Namespace), project, issue], title: issue.title
   .pull-right.assignee-icon
     - if issue.assignee
-      = image_tag avatar_icon(issue.assignee.email, 16), class: "avatar s16"
+      = image_tag avatar_icon(issue.assignee, 16), class: "avatar s16"
diff --git a/app/views/dashboard/milestones/_merge_request.html.haml b/app/views/dashboard/milestones/_merge_request.html.haml
index 8f5c4cce529b601421a4cb813422e6b86cb99a87..77c46de030b1b3bd56121581f9457828a9e68588 100644
--- a/app/views/dashboard/milestones/_merge_request.html.haml
+++ b/app/views/dashboard/milestones/_merge_request.html.haml
@@ -7,4 +7,4 @@
     = link_to_gfm merge_request.title, [project.namespace.becomes(Namespace), project, merge_request], title: merge_request.title
   .pull-right.assignee-icon
     - if merge_request.assignee
-      = image_tag avatar_icon(merge_request.assignee.email, 16), class: "avatar s16"
+      = image_tag avatar_icon(merge_request.assignee, 16), class: "avatar s16"
diff --git a/app/views/dashboard/milestones/show.html.haml b/app/views/dashboard/milestones/show.html.haml
index 0d204ced7ea339ac57d4f88aad22d19713f832b9..d5c4a44fef674ae709d40b8669d2c9cfe7970b90 100644
--- a/app/views/dashboard/milestones/show.html.haml
+++ b/app/views/dashboard/milestones/show.html.haml
@@ -79,7 +79,7 @@
       - @dashboard_milestone.participants.each do |user|
         %li
           = link_to user, title: user.name, class: "darken" do
-            = image_tag avatar_icon(user.email, 32), class: "avatar s32"
+            = image_tag avatar_icon(user, 32), class: "avatar s32"
             %strong= truncate(user.name, lenght: 40)
             %br
             %small.cgray= user.username
diff --git a/app/views/groups/group_members/_group_member.html.haml b/app/views/groups/group_members/_group_member.html.haml
index b5f359279d579847ac43223569204543958f9f3a..3c19381321aec37e36924f7c34635726ea265fde 100644
--- a/app/views/groups/group_members/_group_member.html.haml
+++ b/app/views/groups/group_members/_group_member.html.haml
@@ -5,7 +5,7 @@
 %li{class: "#{dom_class(member)} js-toggle-container", id: dom_id(member)}
   %span{class: ("list-item-name" if show_controls)}
     - if member.user
-      = image_tag avatar_icon(user.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(user, 16), class: "avatar s16", alt: ''
       %strong
         = link_to user.name, user_path(user)
       %span.cgray= user.username
diff --git a/app/views/groups/milestones/_issue.html.haml b/app/views/groups/milestones/_issue.html.haml
index 09f9b4b896906d07db480142df62bbbe6b241174..9b85d83d6d854cc8e0f48ed78bfd39c3b7edfeb9 100644
--- a/app/views/groups/milestones/_issue.html.haml
+++ b/app/views/groups/milestones/_issue.html.haml
@@ -7,4 +7,4 @@
     = link_to_gfm issue.title, [project.namespace.becomes(Namespace), project, issue], title: issue.title
   .pull-right.assignee-icon
     - if issue.assignee
-      = image_tag avatar_icon(issue.assignee.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(issue.assignee, 16), class: "avatar s16", alt: ''
diff --git a/app/views/groups/milestones/_merge_request.html.haml b/app/views/groups/milestones/_merge_request.html.haml
index d0d1426762b5fb41840f4004bf5b0582150b3a21..e3aa4aad198f558929077e653dd482339f81fd29 100644
--- a/app/views/groups/milestones/_merge_request.html.haml
+++ b/app/views/groups/milestones/_merge_request.html.haml
@@ -7,4 +7,4 @@
     = link_to_gfm merge_request.title, [project.namespace.becomes(Namespace), project, merge_request], title: merge_request.title
   .pull-right.assignee-icon
     - if merge_request.assignee
-      = image_tag avatar_icon(merge_request.assignee.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(merge_request.assignee, 16), class: "avatar s16", alt: ''
diff --git a/app/views/groups/milestones/show.html.haml b/app/views/groups/milestones/show.html.haml
index 0c213f421869190ad434643947ea71cb005d9baf..c6cde97c585298290e62a4447c711bb8014a544c 100644
--- a/app/views/groups/milestones/show.html.haml
+++ b/app/views/groups/milestones/show.html.haml
@@ -87,7 +87,7 @@
       - @group_milestone.participants.each do |user|
         %li
           = link_to user, title: user.name, class: "darken" do
-            = image_tag avatar_icon(user.email, 32), class: "avatar s32"
+            = image_tag avatar_icon(user, 32), class: "avatar s32"
             %strong= truncate(user.name, lenght: 40)
             %br
             %small.cgray= user.username
diff --git a/app/views/layouts/_page.html.haml b/app/views/layouts/_page.html.haml
index 1a883e20e899dea4f3dd4b7e7b3536b137ef6741..352b8040cf4aa871649584aed4d018a273d8461b 100644
--- a/app/views/layouts/_page.html.haml
+++ b/app/views/layouts/_page.html.haml
@@ -18,7 +18,7 @@
       = render partial: 'layouts/collapse_button'
     - if current_user
       = link_to current_user, class: 'sidebar-user' do
-        = image_tag avatar_icon(current_user.email, 60), alt: 'User activity', class: 'avatar avatar s36'
+        = image_tag avatar_icon(current_user, 60), alt: 'User activity', class: 'avatar avatar s36'
         .username
           = current_user.username
   .content-wrapper
diff --git a/app/views/layouts/ci/_page.html.haml b/app/views/layouts/ci/_page.html.haml
index bb5ec727bffbcf55f08f1802b9fd2aa35b26ef3f..ab3e29c3f424c63f106f62c28ddf0fb88cb75a3d 100644
--- a/app/views/layouts/ci/_page.html.haml
+++ b/app/views/layouts/ci/_page.html.haml
@@ -15,7 +15,7 @@
       = render partial: 'layouts/collapse_button'
     - if current_user
       = link_to current_user, class: 'sidebar-user' do
-        = image_tag avatar_icon(current_user.email, 60), alt: 'User activity', class: 'avatar avatar s36'
+        = image_tag avatar_icon(current_user, 60), alt: 'User activity', class: 'avatar avatar s36'
         .username
           = current_user.username
   .content-wrapper
diff --git a/app/views/profiles/show.html.haml b/app/views/profiles/show.html.haml
index 47412e2ef0c2cd9652389da2fc4bdc7deb900537..ac7355dde1fc1f6a112638ff5ed62dc2d4148e5f 100644
--- a/app/views/profiles/show.html.haml
+++ b/app/views/profiles/show.html.haml
@@ -68,7 +68,7 @@
 
     .col-md-5
       .light-well
-        = image_tag avatar_icon(@user.email, 160), alt: '', class: 'avatar s160'
+        = image_tag avatar_icon(@user, 160), alt: '', class: 'avatar s160'
 
         .clearfix
           .profile-avatar-form-option
diff --git a/app/views/projects/_md_preview.html.haml b/app/views/projects/_md_preview.html.haml
index 507757f6a2bb5b1121047ac9fe827d4e52089811..7b21095ea3e8637688f32cbf4ef94bf2e6f4379b 100644
--- a/app/views/projects/_md_preview.html.haml
+++ b/app/views/projects/_md_preview.html.haml
@@ -2,10 +2,10 @@
   .md-header.clearfix
     %ul.center-top-menu
       %li.active
-        = link_to '#md-write-holder', class: 'js-md-write-button', tabindex: '-1' do
+        %a.js-md-write-button(href="#md-write-holder" tabindex="-1")
           Write
       %li
-        = link_to '#md-preview-holder', class: 'js-md-preview-button', tabindex: '-1' do
+        %a.js-md-preview-button(href="md-preview-holder" tabindex="-1")
           Preview
 
     - if defined?(referenced_users) && referenced_users
diff --git a/app/views/projects/_zen.html.haml b/app/views/projects/_zen.html.haml
index 6a41cdbc907a433e216494e1910a4a7c9e897201..63ebfc9381f25bf82a40e5a9fe24904fe8d2cc99 100644
--- a/app/views/projects/_zen.html.haml
+++ b/app/views/projects/_zen.html.haml
@@ -1,10 +1,10 @@
 .zennable
-  %input#zen-toggle-comment.zen-toggle-comment{ tabindex: '-1', type: 'checkbox' }
+  %input#zen-toggle-comment.zen-toggle-comment(tabindex="-1" type="checkbox")
   .zen-backdrop
     - classes << ' js-gfm-input markdown-area'
     = f.text_area attr, class: classes, placeholder: ''
-    = link_to nil, class: 'zen-enter-link', tabindex: '-1' do
+    %a.zen-enter-link(tabindex="-1" href="#")
       %i.fa.fa-expand
       Edit in fullscreen
-    = link_to nil, class: 'zen-leave-link' do
+    %a.zen-leave-link(href="#")
       %i.fa.fa-compress
diff --git a/app/views/projects/milestones/_issue.html.haml b/app/views/projects/milestones/_issue.html.haml
index 88fccfe4981c4e665c299729080f7b37fa2a85ab..133d802aaca1646f60211d3843fa0491b950f7d6 100644
--- a/app/views/projects/milestones/_issue.html.haml
+++ b/app/views/projects/milestones/_issue.html.haml
@@ -1,7 +1,7 @@
 %li{ id: dom_id(issue, 'sortable'), class: 'issue-row', 'data-iid' => issue.iid, 'data-url' => issue_path(issue) }
   .pull-right.assignee-icon
     - if issue.assignee
-      = image_tag avatar_icon(issue.assignee.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(issue.assignee, 16), class: "avatar s16", alt: ''
   %span
     = link_to [@project.namespace.becomes(Namespace), @project, issue] do
       %span.cgray ##{issue.iid}
diff --git a/app/views/projects/milestones/_merge_request.html.haml b/app/views/projects/milestones/_merge_request.html.haml
index 0d7a118569a8943037af86bbadf8dd745cb799e8..a1033607c5de0fb94ede75943e56b1a09b452e57 100644
--- a/app/views/projects/milestones/_merge_request.html.haml
+++ b/app/views/projects/milestones/_merge_request.html.haml
@@ -5,4 +5,4 @@
     = link_to_gfm merge_request.title, [@project.namespace.becomes(Namespace), @project, merge_request], title: merge_request.title
   .pull-right.assignee-icon
     - if merge_request.assignee
-      = image_tag avatar_icon(merge_request.assignee.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(merge_request.assignee, 16), class: "avatar s16", alt: ''
diff --git a/app/views/projects/milestones/show.html.haml b/app/views/projects/milestones/show.html.haml
index 4eeb0621e526c32f1d824679c9ae115982760b88..3a898dfbcfd1f2406da96d2afc8e7c71e4cfd77d 100644
--- a/app/views/projects/milestones/show.html.haml
+++ b/app/views/projects/milestones/show.html.haml
@@ -104,7 +104,7 @@
       - @users.each do |user|
         %li
           = link_to user, title: user.name, class: "darken" do
-            = image_tag avatar_icon(user.email, 32), class: "avatar s32"
+            = image_tag avatar_icon(user, 32), class: "avatar s32"
             %strong= truncate(user.name, lenght: 40)
             %br
             %small.cgray= user.username
diff --git a/app/views/projects/notes/_note.html.haml b/app/views/projects/notes/_note.html.haml
index 1638ad6891ae54e085338d1248e48a81f281c945..5d184730796f9112b6f4db44967b0aa934a089ba 100644
--- a/app/views/projects/notes/_note.html.haml
+++ b/app/views/projects/notes/_note.html.haml
@@ -1,8 +1,8 @@
 %li.timeline-entry{ id: dom_id(note), class: [dom_class(note), "note-row-#{note.id}", ('system-note' if note.system)], data: { discussion: note.discussion_id } }
   .timeline-entry-inner
     .timeline-icon
-      = link_to user_path(note.author) do
-        = image_tag avatar_icon(note.author_email), class: 'avatar s40', alt: ''
+      %a{href: user_path(note.author)}
+        %img.avatar.s40{src: avatar_icon(note.author), alt: ''}
     .timeline-content
       .note-header
         - if note_editable?(note)
@@ -25,7 +25,7 @@
           = '@' + note.author.username
 
         %span.note-last-update
-          = link_to "##{dom_id(note)}", name: dom_id(note), title: "Link here" do
+          %a{name: dom_id(note), href: "##{dom_id(note)}", title: 'Link here'}
             = time_ago_with_tooltip(note.created_at, placement: 'bottom', html_class: 'note_created_ago')
           - if note.updated_at != note.created_at
             %span
diff --git a/app/views/projects/project_members/_project_member.html.haml b/app/views/projects/project_members/_project_member.html.haml
index 860a997cff84c6f7fb10c69a6f8e3caa06face39..76c46d1d8067a7fe7dc855fa09a342c40260dbc6 100644
--- a/app/views/projects/project_members/_project_member.html.haml
+++ b/app/views/projects/project_members/_project_member.html.haml
@@ -4,7 +4,7 @@
 %li{class: "#{dom_class(member)} js-toggle-container project_member_row access-#{member.human_access.downcase}", id: dom_id(member)}
   %span.list-item-name
     - if member.user
-      = image_tag avatar_icon(user.email, 16), class: "avatar s16", alt: ''
+      = image_tag avatar_icon(user, 16), class: "avatar s16", alt: ''
       %strong
         = link_to user.name, user_path(user)
       %span.cgray= user.username
diff --git a/app/views/users/show.html.haml b/app/views/users/show.html.haml
index 11beb3e3239533ecbd60ca6907a712ca3c78af3d..2a64708d07c35b021b779fd0d89656e297e29eb4 100644
--- a/app/views/users/show.html.haml
+++ b/app/views/users/show.html.haml
@@ -9,8 +9,8 @@
 .row
   %section.col-md-7
     .header-with-avatar
-      = link_to avatar_icon(@user.email, 400), target: '_blank' do
-        = image_tag avatar_icon(@user.email, 90), class: "avatar avatar-tile s90", alt: ''
+      = link_to avatar_icon(@user, 400), target: '_blank' do
+        = image_tag avatar_icon(@user, 90), class: "avatar avatar-tile s90", alt: ''
       %h3
         = @user.name
         - if @user == current_user
diff --git a/config/environments/development.rb b/config/environments/development.rb
index d7d6aed1602ca498a7666504b932bbe420c9eedd..827a110c2492ac5349277065d2a992243760bc75 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -24,7 +24,7 @@ Gitlab::Application.configure do
 
   # Expands the lines which load the assets
   # config.assets.debug = true
-  
+
   # Adds additional error checking when serving assets at runtime.
   # Checks for improperly declared sprockets dependencies.
   # Raises helpful error messages.
diff --git a/config/initializers/active_record_query_trace.rb b/config/initializers/active_record_query_trace.rb
new file mode 100644
index 0000000000000000000000000000000000000000..4b3c2803b3b36bc31df1b12500b8bc0bdad0288b
--- /dev/null
+++ b/config/initializers/active_record_query_trace.rb
@@ -0,0 +1,5 @@
+if ENV['ENABLE_QUERY_TRACE']
+  require 'active_record_query_trace'
+
+  ActiveRecordQueryTrace.enabled = 'true'
+end
diff --git a/config/initializers/bullet.rb b/config/initializers/bullet.rb
new file mode 100644
index 0000000000000000000000000000000000000000..95e82966c7ae15536f2b7dc6932f9dc45dc1d6b8
--- /dev/null
+++ b/config/initializers/bullet.rb
@@ -0,0 +1,6 @@
+if ENV['ENABLE_BULLET']
+  require 'bullet'
+
+  Bullet.enable  = true
+  Bullet.console = true
+end
diff --git a/config/initializers/rack_lineprof.rb b/config/initializers/rack_lineprof.rb
new file mode 100644
index 0000000000000000000000000000000000000000..f0c006d811bffe04c02572441f7d5cc329ba0255
--- /dev/null
+++ b/config/initializers/rack_lineprof.rb
@@ -0,0 +1,31 @@
+# The default colors of rack-lineprof can be very hard to look at in terminals
+# with darker backgrounds. This patch tweaks the colors a bit so the output is
+# actually readable.
+if Rails.env.development? and RUBY_ENGINE == 'ruby' and ENV['ENABLE_LINEPROF']
+  Gitlab::Application.config.middleware.use(Rack::Lineprof)
+
+  module Rack
+    class Lineprof
+      class Sample < Rack::Lineprof::Sample.superclass
+        def format(*)
+          formatted = if level == CONTEXT
+                        sprintf "                 | % 3i  %s", line, code
+                      else
+                        sprintf "% 8.1fms %5i | % 3i  %s", ms, calls, line, code
+                      end
+
+          case level
+          when CRITICAL
+            color.red formatted
+          when WARNING
+            color.yellow formatted
+          when NOMINAL
+            color.white formatted
+          else # CONTEXT
+            formatted
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/doc/development/profiling.md b/doc/development/profiling.md
new file mode 100644
index 0000000000000000000000000000000000000000..80c86ef921e9fed698feda43b3c1fa26bc4cfb0a
--- /dev/null
+++ b/doc/development/profiling.md
@@ -0,0 +1,56 @@
+# Profiling
+
+To make it easier to track down performance problems GitLab comes with a set of
+profiling tools, some of these are available by default while others need to be
+explicitly enabled.
+
+## rack-mini-profiler
+
+This Gem is enabled by default in development only. It allows you to see the
+timings of the various components that made up a web request (e.g. the SQL
+queries executed and their execution timings).
+
+## Bullet
+
+Bullet is a Gem that can be used to track down N+1 query problems. Because
+Bullet adds quite a bit of logging noise it's disabled by default. To enable
+Bullet, set the environment variable `ENABLE_BULLET` to a non-empty value before
+starting GitLab. For example:
+
+    ENABLE_BULLET=true bundle exec rails s
+
+Bullet will log query problems to both the Rails log as well as the Chrome
+console.
+
+## ActiveRecord Query Trace
+
+This Gem adds backtraces for every ActiveRecord query in the Rails console. This
+can be useful to track down where a query was executed. Because this Gem adds
+quite a bit of noise (5-10 extra lines per ActiveRecord query) it's disabled by
+default. To use this Gem you'll need to set `ENABLE_QUERY_TRACE` to a non empty
+file before starting GitLab. For example:
+
+    ENABLE_QUERY_TRACE=true bundle exec rails s
+
+## rack-lineprof
+
+This is a Gem that can trace the execution time of code on a per line basis.
+Because this Gem can add quite a bit of overhead it's disabled by default. To
+enable it, set the environment variable `ENABLE_LINEPROF` to a non-empty value.
+For example:
+
+    ENABLE_LINEPROF=true bundle exec rails s
+
+Once enabled you'll need to add a query string parameter to a request to
+actually profile code execution. The name of the parameter is `lineprof` and
+should be set to a regular expression (minus the starting/ending slash) used to
+select what files to profile. To profile all files containing "foo" somewhere in
+the path you'd use the following parameter:
+
+    ?lineprof=foo
+
+Or when filtering for files containing "foo" and "bar" in their path:
+
+    ?lineprof=foo|bar
+
+Once set the profiling output will be displayed in your terminal.
diff --git a/spec/benchmarks/models/project_team_spec.rb b/spec/benchmarks/models/project_team_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..8b039ef731738b6f6afb8873b29ecded195f5c48
--- /dev/null
+++ b/spec/benchmarks/models/project_team_spec.rb
@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+describe ProjectTeam, benchmark: true do
+  describe '#max_member_access' do
+    let(:group)   { create(:group) }
+    let(:project) { create(:empty_project, group: group) }
+    let(:user)    { create(:user) }
+
+    before do
+      project.team << [user, :master]
+
+      5.times do
+        project.team << [create(:user), :reporter]
+
+        project.group.add_user(create(:user), :reporter)
+      end
+    end
+
+    benchmark_subject { project.team.max_member_access(user.id) }
+
+    it { is_expected.to iterate_per_second(35000) }
+  end
+end
diff --git a/spec/helpers/application_helper_spec.rb b/spec/helpers/application_helper_spec.rb
index 742420f550e0591fa1bf5ea8ee651671a717b6bf..1dfae0fbd3fea83a4f0966f20f27d5cfbeb880f2 100644
--- a/spec/helpers/application_helper_spec.rb
+++ b/spec/helpers/application_helper_spec.rb
@@ -99,6 +99,15 @@ describe ApplicationHelper do
 
       helper.avatar_icon('foo@example.com', 20)
     end
+
+    describe 'using a User' do
+      it 'should return an URL for the avatar' do
+        user = create(:user, avatar: File.open(avatar_file_path))
+
+        expect(helper.avatar_icon(user).to_s).
+          to match("/uploads/user/avatar/#{user.id}/banana_sample.gif")
+      end
+    end
   end
 
   describe 'gravatar_icon' do
diff --git a/spec/helpers/projects_helper_spec.rb b/spec/helpers/projects_helper_spec.rb
index 53e56ebff44bd34cb8fc9e23bca8930f449fd49d..f2efb528aeb6cc1c9397e7a5c9a8676286f4085d 100644
--- a/spec/helpers/projects_helper_spec.rb
+++ b/spec/helpers/projects_helper_spec.rb
@@ -70,4 +70,18 @@ describe ProjectsHelper do
       expect(helper.send(:readme_cache_key)).to eq("#{project.path_with_namespace}-nil-readme")
     end
   end
+
+  describe 'link_to_member' do
+    let(:group)   { create(:group) }
+    let(:project) { create(:empty_project, group: group) }
+    let(:user)    { create(:user) }
+
+    describe 'using the default options' do
+      it 'returns an HTML link to the user' do
+        link = helper.link_to_member(project, user)
+
+        expect(link).to match(%r{/u/#{user.username}})
+      end
+    end
+  end
 end