Yandex.Tank is an extendable open source load testing tool for advanced linux users which is especially good as a part of automated load testing suit.

• different load generators supported:
  • Evgeniy Mamchits' phantom is a very fast (100 000+ RPS) shooter written in C++ (default)
  • JMeter is an extendable and widely known one
  • BFG is an experimental Python-based generator that allows you to write your own shooter function (included)
• customizable reports in .html with pretty interactive charts based on highcharts library
• graphite support
• several ammo formats supported like plain url list or access.log
• test autostop plugin
• customizable and extendable monitoring that works over SSH

Documentation at ReadTheDocs

Ask your questions at Stackoverflow, use "load testing" + "yandex" tags.

Evgeniy Mamchits' phantom - Phantom scalable IO Engine

Andrey Pohilko's loadosophia - service for storing and analysing performance test results

Jenkins - an extendable open source continuous integration server that may be used to automate test execution.

Graphite - an enterprise-scale monitoring tool, use it to store your test results and render graphs.