1fi_provider(7) Libfabric v1.12.0rc1 fi_provider(7)
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6 fi_provider - Fabric Interface Providers
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9 Conceptually, a fabric provider may be viewed as a local hardware NIC
10 driver, though a provider is not limited by this definition. The first
11 component of libfabric is a general purpose framework that is capable
12 of handling different types of fabric hardware. All fabric hardware
13 devices and their software drivers are required to support this frame‐
14 work. Devices and the drivers that plug into the libfabric framework
15 are referred to as fabric providers, or simply providers.
16 This distribution of libfabric contains the following providers (al‐
18 though more may be available via run-time plug-ins):
19 Core providers
21 GNI A provider for the Aries interconnect in Cray XC(TM) systems
22 utilizing the user-space Generic Networking Interface. See
23 fi_gni(7) for more information.
24 PSM High-speed InfiniBand networking from Intel. See fi_psm(7) for
26 more information.
27 Sockets
29 A general purpose provider that can be used on any network that
30 supports TCP/UDP sockets. This provider is not intended to pro‐
31 vide performance improvements over regular TCP/UDP sockets, but
32 rather to allow developers to write, test, and debug application
33 code even on platforms that do not have high-speed networking.
34 See fi_sockets(7) for more information.
35 usNIC Ultra low latency Ethernet networking over Cisco userspace VIC
37 adapters. See fi_usnic(7) for more information.
38 Verbs This provider uses the Linux Verbs API for network transport.
40 Application performance is, obviously expected to be similar to
41 that of the native Linux Verbs API. Analogous to the Sockets
42 provider, the Verbs provider is intended to enable developers to
43 write, test, and debug application code on platforms that only
44 have Linux Verbs-based networking. See fi_verbs(7) for more in‐
45 formation.
46 Blue Gene/Q
48 See fi_bgq(7) for more information.
49 EFA A provider for the Amazon EC2 Elastic Fabric Adapter (EFA)
51 (https://aws.amazon.com/hpc/efa/), a custom-built OS bypass
52 hardware interface for inter-instance communication on EC2. See
53 fi_efa(7) for more information.
54 SHM A provider for intranode communication using shared memory. The
56 provider makes use of the Linux kernel feature Cross Memory At‐
57 tach (CMA) which allows processes to have full access to another
58 process' address space. See fi_shm(7) for more information.
59 Utility providers
61 RxM The RxM provider (ofi_rxm) is an utility provider that supports
62 RDM endpoints emulated over MSG endpoints of a core provider.
63 See fi_rxm(7) for more information.
64 RxD The RxD provider (ofi_rxd) is a utility provider that supports
66 RDM endpoints emulated over DGRAM endpoints of a core provider.
67 See fi_rxd(7) for more information.
68 Special providers
70 Hook The hook provider is a special type of provider that can layer
71 over any other provider, unless FI_FABRIC_DIRECT is used. The
72 hook provider is always available, but has no impact unless en‐
73 abled. When enabled, the hook provider will intercept all calls
74 to the underlying core or utility provider(s). The hook
75 provider is useful for capturing performance data or providing
76 debugging information, even in release builds of the library.
77 See fi_hook(7) for more information.
78
80 Core providers implement the libfabric interfaces directly over
81 low-level hardware and software interfaces. They are designed to sup‐
82 port a specific class of hardware, and may be limited to supporting a
83 single NIC. Core providers often only support libfabric features and
84 interfaces that map efficiently to their underlying hardware.
85 Utility providers are distinct from core providers in that they are not
87 associated with specific classes of devices. They instead work with
88 core providers to expand their features, and interact with core
89 providers through libfabric interfaces internally. Utility providers
90 are often used to support a specific endpoint type over a simpler end‐
91 point type. For example, the RXD provider implements reliability over
92 unreliable datagram endpoints. The utility providers will not layer
93 over the sockets provider unless it is explicitly requested.
94 Utility providers show up as a component in the core provider's compo‐
96 nent list. See fi_fabric(3). Utility providers are enabled automati‐
97 cally for core providers that do not support the feature set requested
98 by an application.
99
101 Libfabric provides a general framework for supporting multiple types of
102 fabric objects and their related interfaces. Fabric providers have a
103 large amount of flexibility in selecting which components they are able
104 and willing to support, based on specific hardware constraints.
105 Provider developers should refer to docs/provider for information on
106 functionality supplied by the framework to assist in provider implemen‐
107 tation. To assist in the development of applications, libfabric speci‐
108 fies the following requirements that must be met by any fabric
109 provider, if requested by an application.
110 Note that the instantiation of a specific fabric object is subject to
112 application configuration parameters and need not meet these require‐
113 ments.
114 · A fabric provider must support at least one endpoint type.
116 · All endpoints must support the message queue data transfer interface
118 (fi_ops_msg).
119 · An endpoint that advertises support for a specific endpoint capabili‐
121 ty must support the corresponding data transfer interface.
122 · FI_ATOMIC - fi_ops_atomic
124 · FI_RMA - fi_ops_rma
126 · FI_TAGGED - fi_ops_tagged
128 · Endpoints must support all transmit and receive operations for any
130 data transfer interface that they support.
131 · Exception: If an operation is only usable for an operation that the
133 provider does not support, and support for that operation is conveyed
134 using some other mechanism, the operation may return
135 · FI_ENOSYS. For example, if the provider does not support injected
137 data, it can set the attribute inject_size = 0, and fail all fi_in‐
138 ject operations.
139 · The framework supplies wrappers around the 'msg' operations that can
141 be used. For example, the framework implements the sendv() msg oper‐
142 ation by calling sendmsg(). Providers may reference the general op‐
143 eration, and supply on the sendmsg() implementation.
144 · Providers must set all operations to an implementation. Function
146 pointers may not be left NULL or uninitialized. The framework sup‐
147 plies empty functions that return -FI_ENOSYS which can be used for
148 this purpose.
149 · Endpoints must support the CM interface as follows:
151 · FI_EP_MSG endpoints must support all CM operations.
153 · FI_EP_DGRAM endpoints must support CM getname and setname.
155 · FI_EP_RDM endpoints must support CM getname and setname.
157 · Providers that support connectionless endpoints must support all AV
159 operations (fi_ops_av).
160 · Providers that support memory registration, must support all MR oper‐
162 ations (fi_ops_mr).
163 · Providers should support both completion queues and counters.
165 · If FI_RMA_EVENT is not supported, counter support is limited to local
167 events only.
168 · Completion queues must support the FI_CQ_FORMAT_CONTEXT and
170 FI_CQ_FORMAT_MSG.
171 · Providers that support FI_REMOTE_CQ_DATA shall support FI_CQ_FOR‐
173 MAT_DATA.
174 · Providers that support FI_TAGGED shall support FI_CQ_FORMAT_TAGGED.
176 · A provider is expected to be forward compatible, and must be able to
178 be compiled against expanded fi_xxx_ops structures that define new
179 functions added after the provider was written. Any unknown func‐
180 tions must be set to NULL.
181 · Providers shall document in their man page which features they sup‐
183 port, and any missing requirements.
184 Future versions of libfabric will automatically enable a more complete
186 set of features for providers that focus their implementation on a nar‐
187 row subset of libfabric capabilities.
188
190 Logging is performed using the FI_ERR, FI_LOG, and FI_DEBUG macros.
191 DEFINITIONS
193 #define FI_ERR(prov_name, subsystem, ...)
194 #define FI_LOG(prov_name, prov, level, subsystem, ...)
196 #define FI_DEBUG(prov_name, subsystem, ...)
198 ARGUMENTS
200 prov_name
201 String representing the provider name.
202 prov Provider context structure.
204 level Log level associated with log statement.
206 subsystem
208 Subsystem being logged from.
209 DESCRIPTION
211 FI_ERR Always logged.
212 FI_LOG Logged if the intended provider, log level, and subsystem param‐
214 eters match the user supplied values.
215 FI_DEBUG
217 Logged if configured with the --enable-debug flag.
218
220 fi_gni(7), fi_hook(7), fi_psm(7), fi_sockets(7), fi_usnic(7),
221 fi_verbs(7), fi_bgq(7),
222
224 OpenFabrics.
225Libfabric Programmer's Manual 2020-02-13 fi_provider(7)