User Manual

Rev 2.1-1.0.6

Mellanox Technologies

mlx4_en

A 10/40GigE driver under drivers/net/ethernet/mellanox/mlx4 that handles Ethernet specific

functions and plugs into the netdev mid-layer

1.3.2 mlx5 Driver

mlx5 is the low level driver implementation for the Connect-IB™ adapters designed by Mella-

nox Technologies. Connect-IB™ operates as an InfiniBand adapter. The mlx5 driver is com-

prised of the following kernel modules:

mlx5_core

Acts as a library of common functions (e.g. initializing the device after reset) required by the

Connect-IB™ adapter card.

mlx5_ib

Handles InfiniBand-specific functions and plugs into the InfiniBand midlayer.

libmlx5

libmlx5 is the provider library that implements hardware specific user-space functionality. If

there is no compatibility between the firmware and the driver, the driver will not load and a mes-

sage will be printed in the dmesg.

The following are the Libmlx5 environment variables:

• MLX5_FREEZE_ON_ERROR_CQE

• Causes the process to hang in a loop when completion with error which is not flushed with

error or retry exceeded occurs/

• Otherwise disabled

• MLX5_POST_SEND_PREFER_BF

• Configures every work request that can use blue flame will use blue flame

• Otherwise - blue flame depends on the size of the message and inline indication in the

packet

• MLX5_SHUT_UP_BF

• Disables blue flame feature

• Otherwise - do not disable

• MLX5_SINGLE_THREADED

• All spinlocks are disabled

• Otherwise - spinlocks enabled

• Used by applications that are single threaded and would like to save the overhead of taking

spinlocks.

• MLX5_CQE_SIZE

• 64 - completion queue entry size is 64 bytes (default)

• 128 - completion queue entry size is 128 bytes