User Manual

Driver FeaturesRev 2.1-1.0.6
Mellanox Technologies
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number of VFs is larger than 56 entries, some of them will have GID table with only a single
entry which is inadequate if VF's Ethernet device is assigned with an IP address.
When setting num_vfs in mlx4_core module parameter it is important to check that the number
of the assigned IP addresses per VF does not exceed the limit for GID table size.
4.14 CORE-Direct
4.14.1 CORE-Direct Overview
CORE-Direct provides a solution for off loading the MPI collectives operations from the soft-
ware library to the network. CORE-Direct accelerates MPI applications and solves the scalability
issues in large scale systems by eliminating the issues of operating systems noise and jitter.
It addresses the collectives communication scalability problem by off loading a sequence of data-
dependent communications to the Host Channel Adapter (HCA). This solution provides the
hooks needed to support computation and communication overlap. Additionally, it provides a
means to reduce the effects of system noise and application skew on application scalability.
The relevant verbs to be used for CORE-Direct:
• ibv_create_qp_ex
• ibv_modify_cq
• ibv_query_device_ex
• ibv_post_task
Samples programs for reference:
• ibv_task_pingpong, ibv_cc_pingpong
4.15 Ethtool
ethtool is a standard Linux utility for controlling network drivers and hardware, particularly for
wired Ethernet devices. It can be used to:
• Get identification and diagnostic information
• Get extended device statistics
• Control speed, duplex, autonegotiation and flow control for Ethernet devices
• Control checksum offload and other hardware offload features
• Control DMA ring sizes and interrupt moderation