122 lines
4.6 KiB
Markdown
122 lines
4.6 KiB
Markdown
# 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.
|
|
|
|
## Profiling a URL
|
|
|
|
There is a `Gitlab::Profiler.profile` method, and corresponding
|
|
`bin/profile-url` script, that enable profiling a GET or POST request to a
|
|
specific URL, either as an anonymous user (the default) or as a specific user.
|
|
|
|
NOTE: **Note:** The first argument to the profiler is either a full URL
|
|
(including the instance hostname) or an absolute path, including the
|
|
leading slash.
|
|
|
|
When using the script, command-line documentation is available by passing no
|
|
arguments.
|
|
|
|
When using the method in an interactive console session, any changes to the
|
|
application code within that console session will be reflected in the profiler
|
|
output.
|
|
|
|
For example:
|
|
|
|
```ruby
|
|
Gitlab::Profiler.profile('/my-user')
|
|
# Returns a RubyProf::Profile for the regular operation of this request
|
|
class UsersController; def show; sleep 100; end; end
|
|
Gitlab::Profiler.profile('/my-user')
|
|
# Returns a RubyProf::Profile where 100 seconds is spent in UsersController#show
|
|
```
|
|
|
|
For routes that require authorization you will need to provide a user to
|
|
`Gitlab::Profiler`. You can do this like so:
|
|
|
|
```ruby
|
|
Gitlab::Profiler.profile('/gitlab-org/gitlab-test', user: User.first)
|
|
```
|
|
|
|
Passing a `logger:` keyword argument to `Gitlab::Profiler.profile` will send
|
|
ActiveRecord and ActionController log output to that logger. Further options are
|
|
documented with the method source.
|
|
|
|
```ruby
|
|
Gitlab::Profiler.profile('/gitlab-org/gitlab-test', user: User.first, logger: Logger.new(STDOUT))
|
|
```
|
|
|
|
There is also a RubyProf printer available:
|
|
`Gitlab::Profiler::TotalTimeFlatPrinter`. This acts like
|
|
`RubyProf::FlatPrinter`, but its `min_percent` option works on the method's
|
|
total time, not its self time. (This is because we often spend most of our time
|
|
in library code, but this comes from calls in our application.) It also offers a
|
|
`max_percent` option to help filter out outer calls that aren't useful (like
|
|
`ActionDispatch::Integration::Session#process`).
|
|
|
|
There is a convenience method for using this,
|
|
`Gitlab::Profiler.print_by_total_time`:
|
|
|
|
```ruby
|
|
result = Gitlab::Profiler.profile('/my-user')
|
|
Gitlab::Profiler.print_by_total_time(result, max_percent: 60, min_percent: 2)
|
|
# Measure Mode: wall_time
|
|
# Thread ID: 70005223698240
|
|
# Fiber ID: 70004894952580
|
|
# Total: 1.768912
|
|
# Sort by: total_time
|
|
#
|
|
# %self total self wait child calls name
|
|
# 0.00 1.017 0.000 0.000 1.017 14 *ActionView::Helpers::RenderingHelper#render
|
|
# 0.00 1.017 0.000 0.000 1.017 14 *ActionView::Renderer#render_partial
|
|
# 0.00 1.017 0.000 0.000 1.017 14 *ActionView::PartialRenderer#render
|
|
# 0.00 1.007 0.000 0.000 1.007 14 *ActionView::PartialRenderer#render_partial
|
|
# 0.00 0.930 0.000 0.000 0.930 14 Hamlit::TemplateHandler#call
|
|
# 0.00 0.928 0.000 0.000 0.928 14 Temple::Engine#call
|
|
# 0.02 0.865 0.000 0.000 0.864 638 *Enumerable#inject
|
|
```
|
|
|
|
To print the profile in HTML format, use the following example:
|
|
|
|
```ruby
|
|
result = Gitlab::Profiler.profile('/my-user')
|
|
|
|
printer = RubyProf::CallStackPrinter.new(result)
|
|
printer.print(File.open('/tmp/profile.html', 'w'))
|
|
```
|
|
|
|
[GitLab-Profiler](https://gitlab.com/gitlab-com/gitlab-profiler) is a project
|
|
that builds on this to add some additional niceties, such as allowing
|
|
configuration with a single Yaml file for multiple URLs, and uploading of the
|
|
profile and log output to S3.
|
|
|
|
For GitLab.com, you can find the latest results here (restricted to GitLab Team members only):
|
|
`https://redash.gitlab.com/dashboard/gitlab-profiler-statistics`
|
|
|
|
## Sherlock
|
|
|
|
Sherlock is a custom profiling tool built into GitLab. Sherlock is _only_
|
|
available when running GitLab in development mode _and_ when setting the
|
|
environment variable `ENABLE_SHERLOCK` to a non empty value. For example:
|
|
|
|
```sh
|
|
ENABLE_SHERLOCK=1 bundle exec rails s
|
|
```
|
|
|
|
Recorded transactions can be found by navigating to `/sherlock/transactions`.
|
|
|
|
## 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:
|
|
|
|
```sh
|
|
ENABLE_BULLET=true bundle exec rails s
|
|
```
|
|
|
|
Bullet will log query problems to both the Rails log as well as the Chrome
|
|
console.
|
|
|
|
As a follow up to finding `N+1` queries with Bullet, consider writing a [QueryRecoder test](query_recorder.md) to prevent a regression.
|