Bug ID 888517: Busy polling leads to high CPU

Last Modified: Oct 16, 2023

Affected Product(s):
BIG-IP Install/Upgrade, LTM(all modules)

Known Affected Versions:
13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,,,, 14.1.3,, 14.1.4, 15.0.0, 15.0.1,,,,, 15.1.0,,,,,, 15.1.1, 15.1.2,, 16.0.0,, 16.0.1,

Fixed In:
16.1.0,, 15.1.3,, 13.1.4

Opened: Mar 09, 2020

Severity: 3-Major


TMM is running at 100 percent CPU even under a light network load. A high number of packet drops and queue full events are reported.


Busy polling runs the TMM CPU usage to 100 percent.


- BIG-IP Virtual Edition. - There are underlying network performance issues causing the transmit queue to be full. For example, a non-SR-IOV virtual machine environment. - Upgrading from BIG-IP v12.x to BIG-IP v14.x.


Correct the underlying networking/virtualization issue. Report in logs and mark down interface when its transmitting queue is full.

Fix Information

Providing visible information with an error message when there is busy polling over a period of time. "Marking down interface because its txq[<queue_num>] has been full for n seconds."

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips