5 ms·

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 be

by hassy 4y ago

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/ https://www.scylladb.com/2021/04/22/on-coordinated-omission/ 2. https://github.com/tsenart/vegeta https://github.com/tsenart/vegeta

imiric 4y ago
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/ https://k6.io/docs/using-k6/scenarios/arrival-rate/ [2]: https://community.k6.io/t/is-k6-safe-from-the-coordinated-omission-problem/1484 https://community.k6.io/t/is-k6-safe-from-the-coordinated-om...
- hassy 4y ago
  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 4y ago
    > 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-arrival-rate/ https://k6.io/docs/using-k6/scenarios/executors/constant-arr... [2]: https://k6.io/docs/using-k6/k6-options/reference#no-connection-reuse https://k6.io/docs/using-k6/k6-options/reference#no-connecti...

by hassy 4y ago

imiric 4y ago

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/ https://k6.io/docs/using-k6/scenarios/arrival-rate/ [2]: https://community.k6.io/t/is-k6-safe-from-the-coordinated-omission-problem/1484 https://community.k6.io/t/is-k6-safe-from-the-coordinated-om...

hassy 4y ago
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 4y ago
  > 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-arrival-rate/ https://k6.io/docs/using-k6/scenarios/executors/constant-arr... [2]: https://k6.io/docs/using-k6/k6-options/reference#no-connection-reuse https://k6.io/docs/using-k6/k6-options/reference#no-connecti...