From 28014f0754860f06e7504510496d7b7c9b235d88 Mon Sep 17 00:00:00 2001 From: Olga Shern Date: Mon, 23 Nov 2015 15:44:49 +0100 Subject: [PATCH] mlx5: add environment variables section to documentation Describe how applications can benefit from CQE compression. Signed-off-by: Olga Shern Signed-off-by: Adrien Mazarguil --- doc/guides/nics/mlx5.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 2d68914408..eb8c042076 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -130,6 +130,19 @@ These options can be modified in the ``.config`` file. This value is always 1 for RX queues since they use a single MP. +Environment variables +~~~~~~~~~~~~~~~~~~~~~ + +- ``MLX5_ENABLE_CQE_COMPRESSION`` + + A nonzero value lets ConnectX-4 return smaller completion entries to + improve performance when PCI backpressure is detected. It is most useful + for scenarios involving heavy traffic on many queues. + + Since the additional software logic necessary to handle this mode can + lower performance when there is no backpressure, it is not enabled by + default. + Run-time configuration ~~~~~~~~~~~~~~~~~~~~~~ -- 2.20.1