Why does rabbitmq's consumption experience jagged pauses

[ponponon]

Describe the bug

Whether it's the publisher or the consumer, the rate drops to zero at fixed intervals. Is this due to the RabbitMQ server pausing for garbage collection?

If observing a single queue leads to an unreliable conclusion about GC pauses, the same pattern holds globally. The entire RabbitMQ instance seems to pause approximately every 30 seconds. Why is this happening? Is RabbitMQ under excessive load? How can we specifically analyze and troubleshoot whether these GC pauses are caused by high load or other factors?

Reproduction steps

When using RabbitMQ 3.12.14 with a sufficiently large number of queues and consumers, the issue is 100% reproducible.

Expected behavior

I believe both sending consumption and consumption tasks should be smooth. Why does the consumption curve show metrics resetting to zero at fixed intervals? I want to understand the cause. If this is an abnormal phenomenon, I want to know how to prevent it.

Additional context

I deployed it using Debian 10 + Docker.

The machine configuration is 24 cores and 48GB RAM, with top-tier cloud SSD storage.