In this blog post of 2014, Jerry Kuch describes a performance study of RabbitMQ on Google Compute Engine. It demonstrated the ability to receive and deliver more than one million messages per second (a sustained combined ingress/egress of over two million messages per second).
At this high rate of combined ingress (1,345,531 messages per second) and egress (1,413,840 messages per second), RabbitMQ was keeping up with load and that only 2,343 messages are temporarily accumulated in its queues awaiting delivery.
Habari! Blog 