[Bloat] Tuning fq_codel for 40Gb rates

[Andrew Falanga (afalanga)]

Hello,

I've been reading over some papers on the Buffer Bloat site.  This one in particular has been quite informative: https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/#tuning-fq-codel.  I have a private LAN in which several systems are connected via an enterprise class 40Gb switch. I'm tuning the settings for fq_codel, the QDisc chosen to eliminate many problems seen earlier.  This article mentions how fq_codel is well tuned for 1 and 10Gb speeds and makes mention of slower speeds.  Are there suggestions about how to tune the parameters for 40Gb?  I'm adjusting the parameters and the BQL values attempting to achieve as close to 40Gb speeds as possible.  The systems are CentOS 7.6 (kernel 3.10.0) and a Mellanox NIC (Connectx 4).  The network is configured for 9000 byte MTUs.  In lieu of this, I'm setting the quantum value to 9014.



Andrew Falanga
ENGINEER - SIG SYSTEM SOFTWARE
MSIG Equipment Engineering
Micron Technology, Inc.
Office: +1 (208) 368-4022  Fax: (208)368-2807

Email: 
afalanga at micron.com