- 11 Apr, 2016 1 commit
-
-
Yorick Peterse authored
This makes it easier to query, simplifies the code, and makes it possible to figure out what transaction the data belongs to (simply because it's now stored _in_ the transaction). This new setup keeps track of both the real/wall time _and_ CPU time spent in a block, both measured using milliseconds (to keep all units the same).
-
- 08 Apr, 2016 2 commits
-
-
Yorick Peterse authored
This allows us to track how much time of a transaction is spent in dealing with cached data.
-
Yorick Peterse authored
This changes the timestamp of metrics to be more accurate/unique by using Time#to_f combined with a small random jitter value. This combination hopefully reduces the amount of collisions, though there's no way to fully prevent any from occurring. Fixes gitlab-com/operations#175
-
- 25 Jan, 2016 1 commit
-
-
Yorick Peterse authored
This ensures that an instrumented method that doesn't take arguments reports an arity of 0, instead of -1. If Ruby had a proper method for finding out the required arguments of a method (e.g. Method#required_arguments) this would not have been an issue. Sadly the only two methods we have are Method#parameters and Method#arity, and both are equally painful to use. Fixes gitlab-org/gitlab-ce#12450
-
- 13 Jan, 2016 2 commits
-
-
Yorick Peterse authored
Sampling data at a fixed interval means we can potentially miss data from events occurring between sampling intervals. For example, say we sample data every 15 seconds but Unicorn workers get killed after 10 seconds. In this particular case it's possible to miss interesting data as the sampler will never get to actually submitting data. To work around this (at least for the most part) the sampling interval is randomized as following: 1. Take the user specified sampling interval (15 seconds by default) 2. Divide it by 2 (referred to as "half" below) 3. Generate a range (using a step of 0.1) from -"half" to "half" 4. Every time the sampler goes to sleep we'll grab the user provided interval and add a randomly chosen "adjustment" to it while making sure we don't pick the same value twice in a row. For a specified timeout of 15 this means the actual intervals can be anywhere between 7.5 and 22.5, but never can the same interval be used twice in a row. The rationale behind this change is that on dev.gitlab.org I'm sometimes seeing certain Gitlab::Git/Rugged objects being retained, but only for a few minutes every 24 hours. Knowing the code of Gitlab and how much memory it uses/leaks I suspect we're missing data due to workers getting terminated before the sampler can write its data to InfluxDB.
-
Yorick Peterse authored
-
- 12 Jan, 2016 2 commits
-
-
Yorick Peterse authored
Where a vew is called from doesn't matter as much. We already know what action they belong to and this is more than enough information. By removing the file/line number from the list of tags we should also be able to reduce the number of series stored in InfluxDB.
-
Yorick Peterse authored
This gives a very rough estimate of how much memory is allocated during a transaction. This only works reliably when using a single-threaded application server and a Ruby implementation with a GIL as otherwise memory allocated by other threads might skew the statistics. Sadly there's no way around this as Ruby doesn't provide a reliable way of gathering accurate object sizes upon allocation on a per-thread basis.
-
- 11 Jan, 2016 1 commit
-
-
Yorick Peterse authored
Without this it's impossible to find out what methods/views/queries are executed by a certain controller or Sidekiq worker. While this will increase the total number of series it should stay within reasonable limits due to the amount of "actions" being small enough.
-
- 07 Jan, 2016 3 commits
-
-
Yorick Peterse authored
Since filtering by these values is very rare (they're mostly just displayed as-is) we don't need to waste any index space by saving them as tags. By storing them as values we also greatly reduce the number of series in InfluxDB.
-
Yorick Peterse authored
While useful for finding out what methods/views belong to a transaction this might result in too much data being stored in InfluxDB.
-
Yorick Peterse authored
This reverts commit 7549102b. Apparently I was wrong about ActiveSupport::Notifications::Event#duration returning the duration in seconds, instead it returns it in milliseconds already.
-
- 06 Jan, 2016 1 commit
-
-
Yorick Peterse authored
Transaction timings are also already stored in milliseconds, this keeps things consistent.
-
- 04 Jan, 2016 5 commits
-
-
Yorick Peterse authored
This ensures Rails and Sidekiq transactions are split into the series "rails_transactions" and "sidekiq_transactions" respectively.
-
Yorick Peterse authored
This removes the need for any tags to differentiate between Sidekiq and Rails statistics while still being able to separate the two.
-
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.
-
Yorick Peterse authored
-
Yorick Peterse authored
This will be used to store/increment the total query/view rendering timings on a per transaction basis. This in turn can greatly reduce the amount of metrics stored.
-
- 31 Dec, 2015 4 commits
-
-
Yorick Peterse authored
This isn't hugely useful and mostly wastes InfluxDB space. We can re-add this whenever needed (but only once we really need it).
-
Yorick Peterse authored
This removes the need for tagging all metrics with a "process_type" tag.
-
Yorick Peterse authored
This particular setup had 3 problems: 1. Storing SQL queries as tags is very inefficient as InfluxDB ends up indexing every query (and they can get pretty large). Storing these as values instead means we can't always display the SQL as easily. 2. We already instrument ActiveRecord query methods, thus we already have timing information about database queries. 3. SQL obfuscation is difficult to get right and I'd rather not expose sensitive data by accident.
-
Yorick Peterse authored
While it's useful to keep track of the different versions (Ruby, GitLab, etc) doing so for every point wastes disk space and possibly also RAM (which InfluxDB is all to eager to gobble up). If we want to see the performance differences between different GitLab versions simply looking at the performance since the last release date should suffice.
-
- 29 Dec, 2015 2 commits
-
-
Yorick Peterse authored
This removes the need for Sidekiq and any overhead/problems introduced by TCP. There are a few things to take into account: 1. When writing data to InfluxDB you may still get an error if the server becomes unavailable during the write. Because of this we're catching all exceptions and just ignore them (for now). 2. Writing via UDP apparently requires the timestamp to be in nanoseconds. Without this data either isn't written properly. 3. Due to the restrictions on UDP buffer sizes we're writing metrics one by one, instead of writing all of them at once.
-
Yorick Peterse authored
Newlines aren't really needed and they may mess with InfluxDB's line protocol.
-
- 28 Dec, 2015 1 commit
-
-
Yorick Peterse authored
-
- 17 Dec, 2015 14 commits
-
-
Yorick Peterse authored
This allows us to track the counts of actual classes instead of "T_XXX" nodes. This is only enabled on CRuby as it uses CRuby specific APIs.
-
Yorick Peterse authored
This will be used to (for example) instrument all ActiveRecord models.
-
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.
-
Yorick Peterse authored
This makes it possible to determine if a method should be instrumented or not using a block.
-
Yorick Peterse authored
This allows the information to be displayed when using certain functions (e.g. top()) as well as making it easier to aggregate on a per file basis.
-
Yorick Peterse authored
InfluxDB escapes double quotes upon output which makes it a pain to deal with. This ensures that if we're using PostgreSQL we don't store any queries containing double quotes in InfluxDB, solving the escaping problem.
-
Yorick Peterse authored
-
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.
-
Yorick Peterse authored
This makes it easier to instrument multiple modules without having to type the full namespace over and over again.
-
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.
-
Yorick Peterse authored
This ensures that methods such as "==" can be instrumented without producing syntax errors.
-
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).
-
Yorick Peterse authored
This is faster than using define_method since we don't have to keep block bindings around.
-
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.
-