12 files changed, 463 insertions, 12 deletions

diff --git a/doc/README.md b/doc/README.md
index 7d4f84857e0..1efed2871f9 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -67,6 +67,7 @@
 - [Reply by email](incoming_email/README.md) Allow users to comment on issues and merge requests by replying to notification emails.
 - [Migrate GitLab CI to CE/EE](migrate_ci_to_ce/README.md) Follow this guide to migrate your existing GitLab CI data to GitLab CE/EE.
 - [Git LFS configuration](workflow/lfs/lfs_administration.md)
+- [GitLab Performance Monitoring](monitoring/performance/introduction.md) Configure GitLab and InfluxDB for measuring performance metrics
 
 ## Contributor documentation
 
diff --git a/doc/administration/environment_variables.md b/doc/administration/environment_variables.md
index 1eb3a74d304..42a27dcf6d6 100644
--- a/doc/administration/environment_variables.md
+++ b/doc/administration/environment_variables.md
@@ -17,6 +17,8 @@ DATABASE_URL | url | For example: postgresql://localhost/blog_development?pool=5
 GITLAB_EMAIL_FROM | email | Email address used in the "From" field in mails sent by GitLab
 GITLAB_EMAIL_DISPLAY_NAME | string | Name used in the "From" field in mails sent by GitLab
 GITLAB_EMAIL_REPLY_TO | email | Email address used in the "Reply-To" field in mails sent by GitLab
+GITLAB_UNICORN_MEMORY_MIN | integer | The minimum memory threshold (in bytes) for the Unicorn worker killer
+GITLAB_UNICORN_MEMORY_MAX | integer | The maximum memory threshold (in bytes) for the Unicorn worker killer
 
 ## Complete database variables
 
diff --git a/doc/ci/variables/README.md b/doc/ci/variables/README.md
index b99ea25a3fe..862cacda586 100644
--- a/doc/ci/variables/README.md
+++ b/doc/ci/variables/README.md
@@ -56,7 +56,7 @@ export CI_SERVER_VERSION=""
 ```
 
 ### YAML-defined variables
-**This feature requires GitLab Runner 0.5.0 or higher**
+**This feature requires GitLab Runner 0.5.0 or higher and GitLab CI 7.14 or higher **
 
 GitLab CI allows you to add to `.gitlab-ci.yml` variables that are set in build environment.
 The variables are stored in repository and are meant to store non-sensitive project configuration, ie. RAILS_ENV or DATABASE_URL.
diff --git a/doc/ci/yaml/README.md b/doc/ci/yaml/README.md
index fd0d49de4e4..3b594df659d 100644
--- a/doc/ci/yaml/README.md
+++ b/doc/ci/yaml/README.md
@@ -135,10 +135,9 @@ thus allowing to fine tune them.
 ### cache
 
 `cache` is used to specify a list of files and directories which should be
-cached between builds. Caches are stored according to the branch/ref and the
-job name. They are not currently shared between different job names or between
-branches/refs, which means that caching will benefit you if you push subsequent
-commits to an existing feature branch.
+cached between builds.
+
+**By default the caching is enabled per-job and per-branch.**
 
 If `cache` is defined outside the scope of the jobs, it means it is set
 globally and all jobs will use its definition.
@@ -152,6 +151,59 @@ cache:
   - binaries/
 ```
 
+#### cache:key
+
+_**Note:** Introduced in GitLab Runner v1.0.0._
+
+The `key` directive allows you to define the affinity of caching
+between jobs, allowing to have a single cache for all jobs,
+cache per-job, cache per-branch or any other way you deem proper.
+
+This allows you to fine tune caching, allowing you to cache data between different jobs or even different branches.
+The `cache:key` variable can use any of the [predefined variables](../variables/README.md):
+
+Example configurations:
+
+To enable per-job caching:
+
+    ```yaml
+    cache:
+      key: "$CI_BUILD_NAME"
+      untracked: true
+    ```
+
+To enable per-branch caching:
+
+    ```yaml
+    cache:
+      key: "$CI_BUILD_REF_NAME"
+      untracked: true
+    ```
+
+To enable per-job and per-branch caching:
+
+    ```yaml
+    cache:
+      key: "$CI_BUILD_NAME/$CI_BUILD_REF_NAME"
+      untracked: true
+    ```
+
+To enable per-branch and per-stage caching:
+
+    ```yaml
+    cache:
+      key: "$CI_BUILD_STAGE/$CI_BUILD_REF_NAME"
+      untracked: true
+    ```
+
+If you use **Windows Batch** to run your shell scripts you need to replace the `$` with `%`:
+
+    ```yaml
+    cache:
+      key: "%CI_BUILD_STAGE%/%CI_BUILD_REF_NAME%"
+      untracked: true
+    ```
+
 ## Jobs
 
 `.gitlab-ci.yml` allows you to specify an unlimited number of jobs. Each job
diff --git a/doc/install/installation.md b/doc/install/installation.md
index 00030729a4b..4772ed3c566 100644
--- a/doc/install/installation.md
+++ b/doc/install/installation.md
@@ -107,9 +107,16 @@ Then select 'Internet Site' and press enter to confirm the hostname.
 
 ## 2. Ruby
 
-The use of Ruby version managers such as [RVM](https://rvm.io/), [rbenv](https://github.com/sstephenson/rbenv) or [chruby](https://github.com/postmodern/chruby) with GitLab in production frequently leads to hard to diagnose problems. For example, GitLab Shell is called from OpenSSH and having a version manager can prevent pushing and pulling over SSH. Version managers are not supported and we strongly advise everyone to follow the instructions below to use a system Ruby.
+_**Note:** The current supported Ruby versions are 2.1.x. Ruby 2.2 and 2.3 are
+currently not supported._
 
-Remove the old Ruby 1.8 if present
+The use of Ruby version managers such as [RVM], [rbenv] or [chruby] with GitLab
+in production, frequently leads to hard to diagnose problems. For example,
+GitLab Shell is called from OpenSSH, and having a version manager can prevent
+pushing and pulling over SSH. Version managers are not supported and we strongly
+advise everyone to follow the instructions below to use a system Ruby.
+
+Remove the old Ruby 1.8 if present:
 
     sudo apt-get remove ruby1.8
 
@@ -555,3 +562,7 @@ this is likely due to an outdated Nginx or Apache configuration, or a missing or
 misconfigured gitlab-workhorse instance. Double-check that you've
 [installed Go](#3-go), [installed gitlab-workhorse](#install-gitlab-workhorse),
 and correctly [configured Nginx](#site-configuration).
+
+[RVM]: https://rvm.io/ "RVM Homepage"
+[rbenv]: https://github.com/sstephenson/rbenv "rbenv on GitHub"
+[chruby]: https://github.com/postmodern/chruby "chruby on GitHub"
diff --git a/doc/install/requirements.md b/doc/install/requirements.md
index c0ccdd37458..c0425f27ab1 100644
--- a/doc/install/requirements.md
+++ b/doc/install/requirements.md
@@ -32,15 +32,18 @@ Please consider using a virtual machine to run GitLab.
 
 ## Ruby versions
 
-GitLab requires Ruby (MRI) 2.1
+GitLab requires Ruby (MRI) 2.1.x and currently does not work with versions 2.2
+and 2.3.
+
 You will have to use the standard MRI implementation of Ruby.
-We love [JRuby](http://jruby.org/) and [Rubinius](http://rubini.us/) but GitLab needs several Gems that have native extensions.
+We love [JRuby](http://jruby.org/) and [Rubinius](http://rubini.us/) but GitLab
+needs several Gems that have native extensions.
 
 ## Hardware requirements
 
 ### Storage
 
-The necessary hard drive space largely depends on the size of the repos you want to store in GitLab but as a *rule of thumb* you should have at least as much free space as all your repos combined take up. 
+The necessary hard drive space largely depends on the size of the repos you want to store in GitLab but as a *rule of thumb* you should have at least as much free space as all your repos combined take up.
 
 If you want to be flexible about growing your hard drive space in the future consider mounting it using LVM so you can add more hard drives when you need them.
 
@@ -109,4 +112,4 @@ On a very active server (10,000 active users) the Sidekiq process can use 1GB+ o
 - Firefox (Latest released version and [latest ESR version](https://www.mozilla.org/en-US/firefox/organizations/))
 - Safari 7+ (known problem: required fields in html5 do not work)
 - Opera (Latest released version)
-- Internet Explorer (IE) 10+ but please make sure that you have the `Compatibility View` mode disabled.
\ No newline at end of file
+- Internet Explorer (IE) 10+ but please make sure that you have the `Compatibility View` mode disabled.
diff --git a/doc/monitoring/performance/gitlab_configuration.md b/doc/monitoring/performance/gitlab_configuration.md
new file mode 100644
index 00000000000..b856e7935a3
--- /dev/null
+++ b/doc/monitoring/performance/gitlab_configuration.md
@@ -0,0 +1,39 @@
+# GitLab Configuration
+
+GitLab Performance Monitoring is disabled by default. To enable it and change any of its
+settings, navigate to the Admin area in **Settings > Metrics**
+(`/admin/application_settings`).
+
+The minimum required settings you need to set are the InfluxDB host and port.
+Make sure _Enable InfluxDB Metrics_ is checked and hit **Save** to save the
+changes.
+
+---
+
+![GitLab Performance Monitoring Admin Settings](img/metrics_gitlab_configuration_settings.png)
+
+---
+
+Finally, a restart of all GitLab processes is required for the changes to take
+effect:
+
+```bash
+# For Omnibus installations
+sudo gitlab-ctl restart
+
+# For installations from source
+sudo service gitlab restart
+```
+
+## Pending Migrations
+
+When any migrations are pending, the metrics are disabled until the migrations
+have been performed.
+
+---
+
+Read more on:
+
+- [Introduction to GitLab Performance Monitoring](introduction.md)
+- [InfluxDB Configuration](influxdb_configuration.md)
+- [InfluxDB Schema](influxdb_schema.md)
diff --git a/doc/monitoring/performance/img/metrics_gitlab_configuration_settings.png b/doc/monitoring/performance/img/metrics_gitlab_configuration_settings.png
new file mode 100644
index 00000000000..14d82b6ac98
--- /dev/null
+++ b/doc/monitoring/performance/img/metrics_gitlab_configuration_settings.png
diff --git a/doc/monitoring/performance/influxdb_configuration.md b/doc/monitoring/performance/influxdb_configuration.md
new file mode 100644
index 00000000000..3a2b598b78f
--- /dev/null
+++ b/doc/monitoring/performance/influxdb_configuration.md
@@ -0,0 +1,192 @@
+# InfluxDB Configuration
+
+The default settings provided by [InfluxDB] are not sufficient for a high traffic
+GitLab environment. The settings discussed in this document are based on the
+settings GitLab uses for GitLab.com, depending on your own needs you may need to
+further adjust them.
+
+If you are intending to run InfluxDB on the same server as GitLab, make sure
+you have plenty of RAM since InfluxDB can use quite a bit depending on traffic.
+
+Unless you are going with a budget setup, it's advised to run it separately.
+
+## Requirements
+
+- InfluxDB 0.9.5 or newer
+- A fairly modern version of Linux
+- At least 4GB of RAM
+- At least 10GB of storage for InfluxDB data
+
+Note that the RAM and storage requirements can differ greatly depending on the
+amount of data received/stored. To limit the amount of stored data users can
+look into [InfluxDB Retention Policies][influxdb-retention].
+
+## Installation
+
+Installing InfluxDB is out of the scope of this document. Please refer to the
+[InfluxDB documentation].
+
+## InfluxDB Server Settings
+
+Since InfluxDB has many settings that users may wish to customize themselves
+(e.g. what port to run InfluxDB on), we'll only cover the essentials.
+
+The configuration file in question is usually located at
+`/etc/influxdb/influxdb.conf`. Whenever you make a change in this file,
+InfluxDB needs to be restarted.
+
+### Storage Engine
+
+InfluxDB comes with different storage engines and as of InfluxDB 0.9.5 a new
+storage engine is available, called [TSM Tree]. All users **must** use the new
+`tsm1` storage engine as this [will be the default engine][tsm1-commit] in
+upcoming InfluxDB releases.
+
+Make sure you have the following in your configuration file:
+
+```
+[data]
+  dir = "/var/lib/influxdb/data"
+  engine = "tsm1"
+```
+
+### Admin Panel
+
+Production environments should have the InfluxDB admin panel **disabled**. This
+feature can be disabled by adding the following to your InfluxDB configuration
+file:
+
+```
+[admin]
+  enabled = false
+```
+
+### HTTP
+
+HTTP is required when using the [InfluxDB CLI] or other tools such as Grafana,
+thus it should be enabled. When enabling make sure to _also_ enable
+authentication:
+
+```
+[http]
+  enabled = true
+  auth-enabled = true
+```
+
+_**Note:** Before you enable authentication, you might want to [create an
+admin user](#create-a-new-admin-user)._
+
+### UDP
+
+GitLab writes data to InfluxDB via UDP and thus this must be enabled. Enabling
+UDP can be done using the following settings:
+
+```
+[[udp]]
+  enabled = true
+  bind-address = ":8089"
+  database = "gitlab"
+  batch-size = 1000
+  batch-pending = 5
+  batch-timeout = "1s"
+  read-buffer = 209715200
+```
+
+This does the following:
+
+1. Enable UDP and bind it to port 8089 for all addresses.
+2. Store any data received in the "gitlab" database.
+3. Define a batch of points to be 1000 points in size and allow a maximum of
+   5 batches _or_ flush them automatically after 1 second.
+4. Define a UDP read buffer size of 200 MB.
+
+One of the most important settings here is the UDP read buffer size as if this
+value is set too low, packets will be dropped. You must also make sure the OS
+buffer size is set to the same value, the default value is almost never enough.
+
+To set the OS buffer size to 200 MB, on Linux you can run the following command:
+
+```bash
+sysctl -w net.core.rmem_max=209715200
+```
+
+To make this permanent, add the following to `/etc/sysctl.conf` and restart the
+server:
+
+```bash
+net.core.rmem_max=209715200
+```
+
+It is **very important** to make sure the buffer sizes are large enough to
+handle all data sent to InfluxDB as otherwise you _will_ lose data. The above
+buffer sizes are based on the traffic for GitLab.com. Depending on the amount of
+traffic, users may be able to use a smaller buffer size, but we highly recommend
+using _at least_ 100 MB.
+
+When enabling UDP, users should take care to not expose the port to the public,
+as doing so will allow anybody to write data into your InfluxDB database (as
+[InfluxDB's UDP protocol][udp] doesn't support authentication). We recommend either
+whitelisting the allowed IP addresses/ranges, or setting up a VLAN and only
+allowing traffic from members of said VLAN.
+
+## Create a new admin user
+
+If you want to [enable authentication](#http), you might want to [create an
+admin user][influx-admin]:
+
+```
+influx -execute "CREATE USER jeff WITH PASSWORD '1234' WITH ALL PRIVILEGES"
+```
+
+## Create the `gitlab` database
+
+Once you get InfluxDB up and running, you need to create a database for GitLab.
+Make sure you have changed the [storage engine](#storage-engine) to `tsm1`
+before creating a database.
+
+_**Note:** If you [created an admin user](#create-a-new-admin-user) and enabled
+[HTTP authentication](#http), remember to append the username (`-username <username>`)
+and password (`-password <password>`)  you set earlier to the commands below._
+
+Run the following command to create a database named `gitlab`:
+
+```bash
+influx -execute 'CREATE DATABASE gitlab'
+```
+
+The name **must** be `gitlab`, do not use any other name.
+
+Next, make sure that the database was successfully created:
+
+```bash
+influx -execute 'SHOW DATABASES'
+```
+
+The output should be similar to:
+
+```
+name: databases
+---------------
+name
+_internal
+gitlab
+```
+
+That's it! Now your GitLab instance should send data to InfluxDB.
+
+---
+
+Read more on:
+
+- [Introduction to GitLab Performance Monitoring](introduction.md)
+- [GitLab Configuration](gitlab_configuration.md)
+- [InfluxDB Schema](influxdb_schema.md)
+
+[influxdb-retention]: https://docs.influxdata.com/influxdb/v0.9/query_language/database_management/#retention-policy-management
+[influxdb documentation]: https://docs.influxdata.com/influxdb/v0.9/
+[influxdb cli]: https://docs.influxdata.com/influxdb/v0.9/tools/shell/
+[udp]: https://docs.influxdata.com/influxdb/v0.9/write_protocols/udp/
+[influxdb]: https://influxdata.com/time-series-platform/influxdb/
+[tsm tree]: https://influxdata.com/blog/new-storage-engine-time-structured-merge-tree/
+[tsm1-commit]: https://github.com/influxdata/influxdb/commit/15d723dc77651bac83e09e2b1c94be480966cb0d
+[influx-admin]: https://docs.influxdata.com/influxdb/v0.9/administration/authentication_and_authorization/#create-a-new-admin-user
diff --git a/doc/monitoring/performance/influxdb_schema.md b/doc/monitoring/performance/influxdb_schema.md
new file mode 100644
index 00000000000..a5a8aebd2d1
--- /dev/null
+++ b/doc/monitoring/performance/influxdb_schema.md
@@ -0,0 +1,87 @@
+# InfluxDB Schema
+
+The following measurements are currently stored in InfluxDB:
+
+- `PROCESS_file_descriptors`
+- `PROCESS_gc_statistics`
+- `PROCESS_memory_usage`
+- `PROCESS_method_calls`
+- `PROCESS_object_counts`
+- `PROCESS_transactions`
+- `PROCESS_views`
+
+Here, `PROCESS` is replaced with either `rails` or `sidekiq` depending on the
+process type. In all series, any form of duration is stored in milliseconds.
+
+## PROCESS_file_descriptors
+
+This measurement contains the number of open file descriptors over time. The
+value field `value` contains the number of descriptors.
+
+## PROCESS_gc_statistics
+
+This measurement contains Ruby garbage collection statistics such as the amount
+of minor/major GC runs (relative to the last sampling interval), the time spent
+in garbage collection cycles, and all fields/values returned by `GC.stat`.
+
+## PROCESS_memory_usage
+
+This measurement contains the process' memory usage (in bytes) over time. The
+value field `value` contains the number of bytes.
+
+## PROCESS_method_calls
+
+This measurement contains the methods called during a transaction along with
+their duration, and a name of the transaction action that invoked the method (if
+available). The method call duration is stored in the value field `duration`,
+while the method name is stored in the tag `method`. The tag `action` contains
+the full name of the transaction action. Both the `method` and `action` fields
+are in the following format:
+
+```
+ClassName#method_name
+```
+
+For example, a method called by the `show` method in the `UsersController` class
+would have `action` set to `UsersController#show`.
+
+## PROCESS_object_counts
+
+This measurement is used to store retained Ruby objects (per class) and the
+amount of retained objects. The number of objects is stored in the `count` value
+field while the class name is stored in the `type` tag.
+
+## PROCESS_transactions
+
+This measurement is used to store basic transaction details such as the time it
+took to complete a transaction, how much time was spent in SQL queries, etc. The
+following value fields are available:
+
+| Value | Description |
+| ----- | ----------- |
+| `duration`  | The total duration of the transaction |
+| `allocated_memory` | The amount of bytes allocated while the transaction was running. This value is only reliable when using single-threaded application servers |
+| `method_duration` | The total time spent in method calls |
+| `sql_duration` | The total time spent in SQL queries |
+| `view_duration` | The total time spent in views |
+
+## PROCESS_views
+
+This measurement is used to store view rendering timings for a transaction. The
+following value fields are available:
+
+| Value | Description |
+| ----- | ----------- |
+| `duration` | The rendering time of the view |
+| `view` | The path of the view, relative to the application's root directory |
+
+The `action` tag contains the action name of the transaction that rendered the
+view.
+
+---
+
+Read more on:
+
+- [Introduction to GitLab Performance Monitoring](introduction.md)
+- [GitLab Configuration](gitlab_configuration.md)
+- [InfluxDB Configuration](influxdb_configuration.md)
diff --git a/doc/monitoring/performance/introduction.md b/doc/monitoring/performance/introduction.md
new file mode 100644
index 00000000000..f2460d31302
--- /dev/null
+++ b/doc/monitoring/performance/introduction.md
@@ -0,0 +1,64 @@
+# GitLab Performance Monitoring
+
+GitLab comes with its own application performance measuring system as of GitLab
+8.4, simply called "GitLab Performance Monitoring". GitLab Performance Monitoring is available in both the
+Community and Enterprise editions.
+
+Apart from this introduction, you are advised to read through the following
+documents in order to understand and properly configure GitLab Performance Monitoring:
+
+- [GitLab Configuration](gitlab_configuration.md)
+- [InfluxDB Configuration](influxdb_configuration.md)
+- [InfluxDB Schema](influxdb_schema.md)
+
+## Introduction to GitLab Performance Monitoring
+
+GitLab Performance Monitoring makes it possible to measure a wide variety of statistics
+including (but not limited to):
+
+- The time it took to complete a transaction (a web request or Sidekiq job).
+- The time spent in running SQL queries and rendering HAML views.
+- The time spent executing (instrumented) Ruby methods.
+- Ruby object allocations, and retained objects in particular.
+- System statistics such as the process' memory usage and open file descriptors.
+- Ruby garbage collection statistics.
+
+Metrics data is written to [InfluxDB][influxdb] over [UDP][influxdb-udp]. Stored
+data can be visualized using [Grafana][grafana] or any other application that
+supports reading data from InfluxDB. Alternatively data can be queried using the
+InfluxDB CLI.
+
+## Metric Types
+
+Two types of metrics are collected:
+
+1. Transaction specific metrics.
+1. Sampled metrics, collected at a certain interval in a separate thread.
+
+### Transaction Metrics
+
+Transaction metrics are metrics that can be associated with a single
+transaction. This includes statistics such as the transaction duration, timings
+of any executed SQL queries, time spent rendering HAML views, etc. These metrics
+are collected for every Rack request and Sidekiq job processed.
+
+### Sampled Metrics
+
+Sampled metrics are metrics that can't be associated with a single transaction.
+Examples include garbage collection statistics and retained Ruby objects. These
+metrics are collected at a regular interval. This interval is made up out of two
+parts:
+
+1. A user defined interval.
+1. A randomly generated offset added on top of the interval, the same offset
+   can't be used twice in a row.
+
+The actual interval can be anywhere between a half of the defined interval and a
+half above the interval. For example, for a user defined interval of 15 seconds
+the actual interval can be anywhere between 7.5 and 22.5. The interval is
+re-generated for every sampling run instead of being generated once and re-used
+for the duration of the process' lifetime.
+
+[influxdb]: https://influxdata.com/time-series-platform/influxdb/
+[influxdb-udp]: https://docs.influxdata.com/influxdb/v0.9/write_protocols/udp/
+[grafana]: http://grafana.org/
diff --git a/doc/web_hooks/web_hooks.md b/doc/web_hooks/web_hooks.md
index 6420d65cf1b..c29037e89c2 100644
--- a/doc/web_hooks/web_hooks.md
+++ b/doc/web_hooks/web_hooks.md
@@ -56,7 +56,7 @@ X-Gitlab-Event: Push Hook
       "author": {
         "name": "Jordi Mallach",
         "email": "jordi@softcatala.org"
-      }
+      },
       "added": ["CHANGELOG"],
       "modified": ["app/controller/application.rb"],
       "removed": []