Bug ID 432387: Started TMM threads are limited to power of 2 on VE

Last Modified: Apr 10, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP VE(all modules)

Known Affected Versions:
11.4.0, 11.4.1

Fixed In:

Opened: Oct 01, 2013
Severity: 3-Major
Related AskF5 Article:


Performance may suffer if the TMM threads number is not power of 2 on VE.


Lower throughput or packet dropping could happen on VE.


TMM count is automatically calculated based on vCPUs and memory if the DB variable "provision.tmmcount" is not set. However, lower throughput or packet dropping could happen if it's not the number of power of 2. Please note that TMM might continuously restart if "provision.tmmcount" is manually set. See BZ-410549 for details.


Please provision the VE with the vCPU number to be power of 2

Fix Information

The number of TMM instances provisioned on a virtual instance is automatically rounded down to the closest power of two from the lower of either the number of available vCPUs or the value of the "provision.tmmcount" DB variable. This is done to ensure that traffic distribution functions properly.

Behavior Change