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Diffstat (limited to 'doc/development/instrumentation.md')
| -rw-r--r-- | doc/development/instrumentation.md | 37 |
1 files changed, 18 insertions, 19 deletions
diff --git a/doc/development/instrumentation.md b/doc/development/instrumentation.md index c0192bd6709..c1cf2e77c26 100644 --- a/doc/development/instrumentation.md +++ b/doc/development/instrumentation.md @@ -2,36 +2,35 @@ GitLab Performance Monitoring allows instrumenting of custom blocks of Ruby code. This can be used to measure the time spent in a specific part of a larger -chunk of code. The resulting data is written to a separate series. +chunk of code. The resulting data is stored as a field in the transaction that +executed the block. -To start measuring a block of Ruby code you should use -`Gitlab::Metrics.measure` and give it a name for the series to store the data -in: +To start measuring a block of Ruby code you should use `Gitlab::Metrics.measure` +and give it a name: ```ruby -Gitlab::Metrics.measure(:user_logins) do +Gitlab::Metrics.measure(:foo) do ... end ``` -The first argument of this method is the series name and should be plural. This -name will be prefixed with `rails_` or `sidekiq_` depending on whether the code -was run in the Rails application or one of the Sidekiq workers. In the -above example the final series names would be as follows: +3 values are measured for a block: -- rails_user_logins -- sidekiq_user_logins +1. The real time elapsed, stored in NAME_real_time. +2. The CPU time elapsed, stored in NAME_cpu_time. +3. The call count, stored in NAME_call_count. -Series names should be plural as this keeps the naming style in line with the -other series names. +Both the real and CPU timings are measured in milliseconds. -By default metrics measured using a block contain a single value, "duration", -which contains the number of milliseconds it took to execute the block. Custom -values can be added by passing a Hash as the 2nd argument. Custom tags can be -added by passing a Hash as the 3rd argument. A simple example is as follows: +Multiple calls to the same block will result in the final values being the sum +of all individual values. Take this code for example: ```ruby -Gitlab::Metrics.measure(:example_series, { number: 10 }, { class: self.class.to_s }) do - ... +3.times do + Gitlab::Metrics.measure(:sleep) do + sleep 1 + end end ``` + +Here the final value of `sleep_real_time` will be `3`, _not_ `1`. |