[hassy]

Yep, k6 suffers from coordinated omission [1] with its default settings.

A tool that can send a request at a constant rate i.e. wrk2 or Vegeta [2] is a much better fit for this type of a performance test.

1. https://www.scylladb.com/2021/04/22/on-coordinated-omission/

2. https://github.com/tsenart/vegeta

[imiric]

With its default settings, yes, but k6 can be configured to use an executor that implements the open model[1].

See more discussion here[2].

[1]: https://k6.io/docs/using-k6/scenarios/arrival-rate/

[2]: https://community.k6.io/t/is-k6-safe-from-the-coordinated-om...

[hassy]

Yes indeed but wrk2 or Vegeta is still better for this particular use case (unless k6 has support for setting a constant RPS rate, afaik it does not), as otherwise the overhead of establishing a new TCP connection for a single HTTP request will dominate the benchmark.

[imiric]

> unless k6 has support for setting a constant RPS rate, afaik it does not

Yes it can, via the `constant-arrival-rate` executor[1].

> the overhead of establishing a new TCP connection for a single HTTP request will dominate the benchmark

By default, k6 will reuse TCP connections, and you have to explicitly disable it[2].

I'm not saying that wrk2 or Vegeta wouldn't be a good fit for this test, but k6 is also capable of it, with some minor configuration changes.

[1]: https://k6.io/docs/using-k6/scenarios/executors/constant-arr...

[2]: https://k6.io/docs/using-k6/k6-options/reference#no-connecti...