User Manual

Rev 2.3-1.0.1

Mellanox Technologies

1.4.1.3 mlx4_en Parameters

inline_thold: Threshold for using inline data (int)

Default and max value is 104 bytes. Saves PCI read operation

transaction, packet less then threshold size will be copied to

hw buffer directly.

udp_rss: Enable RSS for incoming UDP traffic (uint)

On by default. Once disabled no RSS for incoming UDP traffic

will be done.

pfctx: Priority based Flow Control policy on TX[7:0]. Per priority

bit mask (uint)

pfcrx: Priority based Flow Control policy on RX[7:0]. Per priority

bit mask (uint)

1.4.2 mlx5 Module Parameters

The mlx5_ib module supports a single parameter used to select the profile which defines the

number of resources supported. The parameter name for selecting the profile is

prof_sel.

The supported values for profiles are:

• 0 - for medium resources, medium performance

• 1 - for low resources

• 2 - for high performance (int) (default)

1.5 Device Capabilities

Normally, an application needs to query the device capabilities before attempting to create a

resource. It is essential for the application to be able to operate over different devices with differ-

ent capabilities.

Specifically, when creating a QP, the user needs to specify the maximum number of outstanding

work requests that the QP supports.

This value should not exceed the queried capabilities. How-

ever, even when you specify a number that does not exceed the queried capability, the verbs can

still fail since some other factors such as the number of scatter/gather entries requested, or the

size of the inline data required, af

fect the maximum possible work requests. Hence an application

should try to decrease this size (halving is a good new value) and retry until it succeeds.