NAME

fi_tcp - The msg sockets Fabric Provider

OVERVIEW

The tcp provider can be used on any system that supports TCP sockets. The provider is not intended to provide performance improvements over regular TCP sockets, but rather to allow developers to write, test,and debug application code even on platforms that do not have high-performance fabric hardware.

SUPPORTED FEATURES

The following features are supported

Endpoint types: FI_EP_MSG is the only supported endpoint type. Reliable datagram endpoint over TCP sockets can be achieved by layering RxM over tcp provider. FI_EP_RDM is supported by layering ofi_rxm provider on top of the tcp provider.
Endpoint capabilities: The tcp provider currently supports FI_MSG, FI_RMA
Progress: Currently tcp provider supports only FI_PROGRESS_MANUAL
Shared Rx Context: The tcp provider supports shared receive context
Multi recv buffers: The tcp provider supports multi recv buffers

RUNTIME PARAMETERS

The tcp provider check for the following enviroment variables -

FI_TCP_IFACE: A specific can be requested with this variable
FI_TCP_PORT_LOW_RANGE/FI_TCP_PORT_HIGH_RANGE: These variables are used to set the range of ports to be used by the tcp provider for its passive endpoint creation. This is useful where only a range of ports are allowed by firewall for tcp connections.
FI_TCP_TX_SIZE: Default tx context size (default: 256)
FI_TCP_RX_SIZE: Default rx context size (default: 256)

LIMITATIONS

The tcp provider is implemented over TCP sockets to emulate libfabric API. Hence the performance may be lower than what an application might see implementing to sockets directly, depending on the types of data transfers the application is trying to achieve.

AUTHORS