fi_provider - Fabric Interface Providers
Conceptually, a fabric provider may be viewed as a local hardware NIC driver,
though a provider is not limited by this definition. The first component of
libfabric is a general purpose framework that is capable of handling different
types of fabric hardware. All fabric hardware devices and their software
drivers are required to support this framework. Devices and the drivers that
plug into the libfabric framework are referred to as fabric providers, or
This distribution of libfabric contains the following providers (although more
may be available via run-time plug-ins):
: A provider for the Aries interconnect in Cray XC(TM) systems
utilizing the user-space Generic Networking Interface
. See fi_gni(7)
for more information.
: High-speed InfiniBand networking from Intel. See fi_psm(7) for more
: A general purpose provider that can be used on any network that
supports TCP/UDP sockets. This provider is not intended to provide performance
improvements over regular TCP/UDP sockets, but rather to allow developers to
write, test, and debug application code even on platforms that do not have
high-speed networking. See fi_sockets(7) for more information.
: Ultra low latency Ethernet networking over Cisco userspace VIC
adapters. See fi_usnic(7) for more information.
: This provider uses the Linux Verbs API for network transport.
Application performance is, obviously expected to be similar to that of the
native Linux Verbs API. Analogous to the Sockets provider, the Verbs provider
is intended to enable developers to write, test, and debug application code on
platforms that only have Linux Verbs-based networking. See fi_verbs(7) for
: See fi_bgq(7) for more information.
: The RxM provider (ofi_rxm) is an utility provider that supports RDM
endpoints emulated over MSG endpoints of a core provider. See fi_rxm(7) for
Core providers implement the libfabric interfaces directly over low-level
hardware and software interfaces. They are designed to support a specific
class of hardware, and may be limited to supporting a single NIC. Core
providers often only support libfabric features and interfaces that map
efficiently to their underlying hardware.
Utility providers are distinct from core providers in that they are not
associated with specific classes of devices. They instead work with core
providers to expand their features, and interact with core providers through
libfabric interfaces internally. Utility providers are often used to support a
specific endpoint type over a simpler endpoint type. For example, the RXD
provider implements reliability over unreliable datagram endpoints. The
utility providers will not layer over the sockets provider unless it is
Utility providers show up as a component in the core provider's component list.
See fi_fabric(3). Utility providers are enabled automatically for core
providers that do not support the feature set requested by an application.
Libfabric provides a general framework for supporting multiple types of fabric
objects and their related interfaces. Fabric providers have a large amount of
flexibility in selecting which components they are able and willing to
support, based on specific hardware constraints. Provider developers should
refer to docs/provider for information on functionality supplied by the
framework to assist in provider implementation. To assist in the development
of applications, libfabric specifies the following requirements that must be
met by any fabric provider, if requested by an application.
Note that the instantiation of a specific fabric object is subject to
application configuration parameters and need not meet these requirements.
- A fabric provider must support at least one endpoint type.
- All endpoints must support the message queue data transfer interface
- An endpoint that advertises support for a specific endpoint capability
must support the corresponding data transfer interface.
- FI_ATOMIC - fi_ops_atomic
- FI_RMA - fi_ops_rma
- FI_TAGGED - fi_ops_tagged
- Endpoints must support all transmit and receive operations for any data
transfer interface that they support.
- Exception: If an operation is only usable for an operation that the
provider does not support, and support for that operation is conveyed
using some other mechanism, the operation may return
- FI_ENOSYS. For example, if the provider does not support injected data, it
can set the attribute inject_size = 0, and fail all fi_inject
- The framework supplies wrappers around the 'msg' operations that can be
used. For example, the framework implements the sendv() msg operation by
calling sendmsg(). Providers may reference the general operation, and
supply on the sendmsg() implementation.
- Providers must set all operations to an implementation. Function pointers
may not be left NULL or uninitialized. The framework supplies empty
functions that return -FI_ENOSYS which can be used for this purpose.
- Endpoints must support the CM interface as follows:
- FI_EP_MSG endpoints must support all CM operations.
- FI_EP_DGRAM endpoints must support CM getname and setname.
- FI_EP_RDM endpoints must support CM getname and setname.
- Providers that support connectionless endpoints must support all AV
- Providers that support memory registration, must support all MR operations
- Providers should support both completion queues and counters.
- If FI_RMA_EVENT is not supported, counter support is limited to local
- Completion queues must support the FI_CQ_FORMAT_CONTEXT and
- Providers that support FI_REMOTE_CQ_DATA shall support
- Providers that support FI_TAGGED shall support FI_CQ_FORMAT_TAGGED.
- A provider is expected to be forward compatible, and must be able to be
compiled against expanded fi_xxx_ops structures that define new functions
added after the provider was written. Any unknown functions must be set to
- Providers shall document in their man page which features they support,
and any missing requirements.
Future versions of libfabric will automatically enable a more complete set of
features for providers that focus their implementation on a narrow subset of
Logging is performed using the FI_ERR, FI_LOG, and FI_DEBUG macros.
#define FI_ERR(prov_name, subsystem, ...)
#define FI_LOG(prov_name, prov, level, subsystem, ...)
#define FI_DEBUG(prov_name, subsystem, ...)
: String representing the provider name.
: Provider context structure.
: Log level associated with log statement.
: Subsystem being logged from.
: Always logged.
: Logged if the intended provider, log level, and subsystem
parameters match the user supplied values.
: Logged if configured with the --enable-debug flag.
fi_gni(7), fi_psm(7), fi_sockets(7), fi_usnic(7), fi_verbs(7), fi_bgq(7),