Jenkins 1.544 + plugin 1.8.1 also fixes this problem for me

The plugin appears to work on a simple job.

I just tested on a multi-configuration job and the throttle plugin doesn't appear to do anything. I'm using Jenkins 1.532.1 and throttle plugin 1.8.1. I created 1 category. I configured 2 multi-configuration jobs to be throttled by that category and to only allow 1 build per node. I then manually started both jobs and found that both jobs ran at the same time.

I just upgraded to Jenkins 1.532.2 and Throttle Concurrent Builds 1.8.1 and I'm still seeing 2 jobs from the same category build at the same time on the same node when there is a limit of 1 job per node for the specified category. In this case one job is from a matrix job and one is a free-style project job.

I can reproduce this with: Jenkins 1.551 and plugin 1.8.2

A matrix with 2 Axis and (for testing) a little shell sleep is supposed to be run only 3 times per node.

Configuration 1:
Throttle this project alone *
Maximum Total Concurrent Builds 0
Maximum Concurrent Builds Per Node 3

Result: All Executors on all Nodes are used

Configuration 2:

Global - Multi-Project Throttle Categories
Category Name: kvm
Maximum Total Concurrent Builds 0
Maximum Concurrent Builds Per Node 3

Throttle this project as part of one or more categories *
Multi-Project Throttle Category *kvm

Result: All Executors on all Nodes are used

Can I help in debugging? where to look?

Looks broken on Jenkins 1.551 + 1.8.2 or Jenkins 1.557 + 1.8.2

Jobs still stacking in queue instead concurrent running on different nodes.

Sorry, I was wrong. I forgot to allow concurrent builds for job itself.

I'm also unable to throttle even very simple matrix jobs, running Jenkins 1.565 and version 1.8.2 of the plugin. The job setup is:

• Throttle this project alone
• Maximum total concurrent builds: 0
• Maximum concurrent builds per node: 1
• One user-defined axis

When I launch it no throttling is done – every available executor starts processing one of the configurations.

I tried throttling by category (changing the project limits 0) and got the same behavior, both for generic limits and node-specific category limits.

How can I help debug this?

See JENKINS-13619 for all issues related to MATRIX jobs.
The new release of the plugin will provide throttling of matrix configurations in "Categories" mode at least

Closing as a duplicate of JENKINS-13619 (fixed in throttle-concurrents-1.8.3)

I think this issue has returned.
I'm using Jenkins 2.32.1
I have 10 executors on my Jenkins installation
I set up 3 jobs, which all have these TCB options set:
Throttle this project as part of one or more categories (set)
Maximum Total Concurrent Builds = 1
Maximum Concurrent Builds Per Node = 1
List of parameters to check: Expensive

If I queue up all 3 jobs, they all three run simultaneously. I expected them to block each other.