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- 04 Jan, 2016 2 commits
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Yorick Peterse authored
This ensures Rails and Sidekiq transactions are split into the series "rails_transactions" and "sidekiq_transactions" respectively.
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Yorick Peterse authored
This makes it easier to see where time is spent without having to aggregate all the individual points in the method_calls series.
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- 31 Dec, 2015 1 commit
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Yorick Peterse authored
This removes the need for tagging all metrics with a "process_type" tag.
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- 17 Dec, 2015 9 commits
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Yorick Peterse authored
This will be used to (for example) instrument all ActiveRecord models.
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Yorick Peterse authored
This ensures we don't end up wasting resources by tracking method calls that only take a few microseconds. By default the threshold is 10 milliseconds but this can be changed using the gitlab.yml configuration file.
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Yorick Peterse authored
This makes it possible to determine if a method should be instrumented or not using a block.
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Yorick Peterse authored
When using instrument_methods/instrument_instance_methods we only want to instrument methods defined directly in a class, not those included via mixins (e.g. whatever RSpec throws in during development). In case an externally included method _has_ to be instrumented we can still use the regular instrument_method/instrument_instance_method methods.
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Yorick Peterse authored
This makes it easier to instrument multiple modules without having to type the full namespace over and over again.
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Yorick Peterse authored
The methods Instrumentation.instrument_methods and Instrumentation.instrument_instance_methods can be used to instrument all methods of a module at once.
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Yorick Peterse authored
The use of ActiveSupport would slow down instrumented method calls by about 180x due to: 1. ActiveSupport itself not being the fastest thing on the planet 2. caller_locations() having quite some overhead The use of caller_locations() has been removed because it's not _that_ useful since we already know the full namespace of receivers and the names of the called methods. The use of ActiveSupport has been replaced with some custom code that's generated using eval() (which can be quite a bit faster than using define_method). This new setup results in instrumented methods only being about 35-40x slower (compared to non instrumented methods).
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Yorick Peterse authored
This is faster than using define_method since we don't have to keep block bindings around.
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Yorick Peterse authored
This adds the ability to write application metrics (e.g. SQL timings) to InfluxDB. These metrics can in turn be visualized using Grafana, or really anything else that can read from InfluxDB. These metrics can be used to track application performance over time, between different Ruby versions, different GitLab versions, etc. == Transaction Metrics Currently the following is tracked on a per transaction basis (a transaction is a Rails request or a single Sidekiq job): * Timings per query along with the raw (obfuscated) SQL and information about what file the query originated from. * Timings per view along with the path of the view and information about what file triggered the rendering process. * The duration of a request itself along with the controller/worker class and method name. * The duration of any instrumented method calls (more below). == Sampled Metrics Certain metrics can't be directly associated with a transaction. For example, a process' total memory usage is unrelated to any running transactions. While a transaction can result in the memory usage going up there's no accurate way to determine what transaction is to blame, this becomes especially problematic in multi-threaded environments. To solve this problem there's a separate thread that takes samples at a fixed interval. This thread (using the class Gitlab::Metrics::Sampler) currently tracks the following: * The process' total memory usage. * The number of file descriptors opened by the process. * The amount of Ruby objects (using ObjectSpace.count_objects). * GC statistics such as timings, heap slots, etc. The default/current interval is 15 seconds, any smaller interval might put too much pressure on InfluxDB (especially when running dozens of processes). == Method Instrumentation While currently not yet used methods can be instrumented to track how long they take to run. Unlike the likes of New Relic this doesn't require modifying the source code (e.g. including modules), it all happens from the outside. For example, to track `User.by_login` we'd add the following code somewhere in an initializer: Gitlab::Metrics::Instrumentation. instrument_method(User, :by_login) to instead instrument an instance method: Gitlab::Metrics::Instrumentation. instrument_instance_method(User, :save) Instrumentation for either all public model methods or a few crucial ones will be added in the near future, I simply haven't gotten to doing so just yet. == Configuration By default metrics are disabled. This means users don't have to bother setting anything up if they don't want to. Metrics can be enabled by editing one's gitlab.yml configuration file (see config/gitlab.yml.example for example settings). == Writing Data To InfluxDB Because InfluxDB is still a fairly young product I expect the worse. Data loss, unexpected reboots, the database not responding, you name it. Because of this data is _not_ written to InfluxDB directly, instead it's queued and processed by Sidekiq. This ensures that users won't notice anything when InfluxDB is giving trouble. The metrics worker can be started in a standalone manner as following: bundle exec sidekiq -q metrics The corresponding class is called MetricsWorker.
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