is 51,000 tests too much in a job?

[Kevin Goess]

Is 51,000 tests too much in a single job?

We're seeing painful slowdowns in the Jenkins UI and this question came up.  Our junit.xml file is about 17MB in size.  Are other people running that number of tests successfully?

[Tim]

I run jobs that have that many, one with about 80,000 tests. of course there's a lot of work going on, but I wouldn't call it a painful slowdown.

[James Nord]

Check how much heap you have allowed jenkins to use.  If too low unit tests will spend a hugely disproportionate % of their time in garbage collection and loading from disk rather than parsing the results (load the prior build to get the failing since for a test, do the next test get the previous result for that test (which normally will now be in memory,but will have been garbage collected and will need loading form the disk again) rinse repeat....

[Kevin Goess]

> Check how much heap you have allowed jenkins to use.  

We're currently running with

     -XX:PermSize=128M -XX:MaxPermSize=512M -Xmx16384M

and the jenkins memory graph under /monitoring shows us maxing out under 12GB, and that seems excessive to me, since we only have about a dozen builds going on. Is 12-16GB there excessive and maybe indicative of a problem, or is that all standard?

[Maciej Jaros]

Kevin Goess (2015-10-09 17:32):

That might depend on what/how you're testing. I've noticed that Maven actually uses a separate JVM. So Jenkins instance heap is one thing but you need to leave room for other processes. As seems if you have many Maven builds then all of them will allocate at least `Xms` memory. So you might want to keep `CATALINA_OPTS` low and `MAVEN_OPTS` as high as you can.

Regards,
Nux.