Bug ID 686190: LRO performance impact with BWC and FastL4 virtual server

Last Modified: Oct 01, 2018

Bug Tracker

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

Known Affected Versions:
13.1.0

Fixed In:
14.0.0, 13.1.0.1

Opened: Sep 28, 2017
Severity: 2-Critical

Symptoms

Using Bandwidth controller (BWC) might result in a very large drop in performance of up to 75%. In this release, Large receive offload (LRO) is enabled by default.

Impact

Very large performance impact to the BWC policy (up to 75%). For example, if the BWC policy rate limit is set to 100Mb, the actual rate limit could be 25Mb.

Conditions

-- BWC is configured. -- Virtual server has a FastL4 profile assigned. -- LRO is enabled (enabled by default in 13.1.0).

Workaround

Disabling LRO recaptures most of the performance degradation related to using FastL4. To disable LRO (this is a system-wide setting), run the following command: tmsh modify sys db tm.largereceiveoffload value disable Important note: Although you can disable LRO to recapture much of the 13.0.0-level performance, you will likely still experience some impact: 2-5% for small files, 17-22% degradation for the '10 requests per connection' benchmark. The only guaranteed way to avoid performance degradation is to remain on version 13.0.0.

Fix Information

None

Behavior Change