Even if Atlassian published some load-test scrips, the last change made to them was more than a year ago, they seem to support only JIRA up to 5.2 and they were never thested on HTTPS.
https://confluence.atlassian.com/display/ATLAS/JIRA+Performance+Testing+with+Grinder
I had to fork them just to fix the HTTPS stuff but they are still failing to run and they are "unsupported", we cannot even add a comment on the documentation page.
If anyone has patched version you are welcome to share them, the fork is on https://bitbucket.org/phoebian/jira-performance-tests- where I already enabled the issue tracker (the original git repo had it disabled).
I'm wondering if load test are really part of the development process, or they were made as a side project, more like an experiment.