load testing

Jan 03, 2024


ab (aka apachebench)


wrk is a modern HTTP benchmarking tool capable of generating significant load when run on a single multi-core CPU. It combines a multithreaded design with scalable event notification systems such as epoll and kqueue.


wrk2 is wrk modifed to produce a constant throughput load, and accurate latency details to the high 9s (i.e. can produce accurate 99.9999%'ile when run long enough). In addition to wrk's arguments, wrk2 takes a throughput argument (in total requests per second) via either the --rate or -R parameters (default is 1000).


hey is a tiny program that sends some load to a web application.


Vegeta is a versatile HTTP load testing tool built out of a need to drill HTTP services with a constant request rate. It can be used both as a command line utility and a library.

(ed: a go library)


Define user behaviour with Python code, and swarm your system with millions of simultaneous users.

we used this to good success on MCT


Fortio runs at a specified query per second (qps) and records an histogram of execution time and calculates percentiles (e.g. p99 ie the response time such as 99% of the requests take less than that number (in seconds, SI unit)). It can run for a set duration, for a fixed number of calls, or until interrupted (at a constant target QPS, or max speed/load per connection/thread).

Fortio is a fast, small (4Mb docker image, minimal dependencies), reusable, embeddable go library as well as a command line tool and server process, the server includes a simple web UI and REST API to trigger run and see graphical representation of the results (both a single latency graph and a multiple results comparative min, max, avg, qps and percentiles graphs).

Fortio also includes a set of server side features (similar to httpbin) to help debugging and testing: request echo back including headers, adding latency or error codes with a probability distribution, tcp echoing, tcp proxying, http fan out/scatter and gather proxy server, GRPC echo/health in addition to http, etc...

Summary of the options as of 2020, by an author of k6 - still a good reasonably fair article

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