Provided by: libfabric-dev_1.11.0-3_amd64 
NAME
fi_getinfo, fi_freeinfo - Obtain / free fabric interface information
fi_allocinfo, fi_dupinfo - Allocate / duplicate an fi_info structure
SYNOPSIS
#include <rdma/fabric.h>
int fi_getinfo(int version, const char *node, const char *service,
uint64_t flags, const struct fi_info *hints, struct fi_info **info);
void fi_freeinfo(struct fi_info *info);
struct fi_info *fi_allocinfo(void);
struct fi_info *fi_dupinfo(const struct fi_info *info);
ARGUMENTS
version
Interface version requested by application.
node Optional, name or fabric address to resolve.
service
Optional, service name or port number of address.
flags Operation flags for the fi_getinfo call.
hints Reference to an fi_info structure that specifies criteria for selecting the
returned fabric information.
info A pointer to a linked list of fi_info structures containing response information.
DESCRIPTION
fi_getinfo returns information about available fabric services for reaching specified node
or service, subject to any provided hints. Callers may specify NULL for node, service,
and hints in order to retrieve information about what providers are available and their
optimal usage models. If no matching fabric information is available, info will be set to
NULL and the call will return -FI_ENODATA.
Based on the input hints, node, and service parameters, a list of fabric domains and
endpoints will be returned. Each fi_info structure will describe an endpoint that meets
the application's specified communication criteria. Each endpoint will be associated with
a domain. Applications can restrict the number of returned endpoints by including
additional criteria in their search hints. Relaxing or eliminating input hints will
increase the number and type of endpoints that are available. Providers that return
multiple endpoints to a single fi_getinfo call should return the endpoints that are
highest performing first. Providers may indicate that an endpoint and domain can support
additional capabilities than those requested by the user only if such support will not
adversely affect application performance or security.
The version parameter is used by the application to request the desired version of the
interfaces. The version determines the format of all data structures used by any of the
fabric interfaces. Applications should use the FI_VERSION(major, minor) macro to indicate
the version, with hard-coded integer values for the major and minor values. The
FI_MAJOR_VERSION and FI_MINOR_VERSION enum values defined in fabric.h specify the latest
version of the installed library. However, it is recommended that the integer values for
FI_MAJOR_VERSION and FI_MINOR_VERSION be used, rather than referencing the enum types in
order to ensure compatibility with future versions of the library. This protects against
the application being built from source against a newer version of the library that
introduces new fields to data structures, which would not be initialized by the
application.
Node, service, or hints may be provided, with any combination being supported. If node is
provided, fi_getinfo will attempt to resolve the fabric address to the given node. If
node is not given, fi_getinfo will attempt to resolve the fabric addressing information
based on the provided hints. Node is commonly used to provide a network address (such as
an IP address) or hostname. Service is usually associated with a transport address (such
as a TCP port number). Node and service parameters may be mapped by providers to native
fabric addresses. Applications may also pass in an FI_ADDR_STR formatted address (see
format details below) as the node parameter. In such cases, the service parameter must be
NULL.
The hints parameter, if provided, may be used to limit the resulting output as indicated
below. As a general rule, specifying a non-zero value for input hints indicates that a
provider must support the requested value or fail the operation with -FI_ENODATA. With
the exception of mode bits, hints that are set to zero are treated as a wildcard. A
zeroed hint value results in providers either returning a default value or a value that
works best for their implementation. Mode bits that are set to zero indicate the
application does not support any modes.
The caller must call fi_freeinfo to release fi_info structures returned by this call.
The fi_allocinfo call will allocate and zero an fi_info structure and all related
substructures. The fi_dupinfo will duplicate a single fi_info structure and all the
substructures within it.
FI_INFO
struct fi_info {
struct fi_info *next;
uint64_t caps;
uint64_t mode;
uint32_t addr_format;
size_t src_addrlen;
size_t dest_addrlen;
void *src_addr;
void *dest_addr;
fid_t handle;
struct fi_tx_attr *tx_attr;
struct fi_rx_attr *rx_attr;
struct fi_ep_attr *ep_attr;
struct fi_domain_attr *domain_attr;
struct fi_fabric_attr *fabric_attr;
struct fid_nic *nic;
};
next Pointer to the next fi_info structure in the list. Will be NULL if no more
structures exist.
caps - fabric interface capabilities
If specified, indicates the desired capabilities of the fabric interfaces.
Supported capabilities are listed in the Capabilities section below.
mode Operational modes supported by the application. See the Mode section below.
addr_format - address format
If specified, indicates the format of addresses referenced by the fabric interfaces
and data structures. Supported formats are listed in the Addressing formats
section below.
src_addrlen - source address length
Indicates the length of the source address. This value must be > 0 if src_addr is
non-NULL. This field will be ignored in hints if FI_SOURCE flag is set, or
src_addr is NULL.
dest_addrlen - destination address length
Indicates the length of the destination address. This value must be > 0 if
dest_addr is non-NULL. This field will be ignored in hints unless the node and
service parameters are NULL or FI_SOURCE flag is set, or if dst_addr is NULL.
src_addr - source address
If specified, indicates the source address. This field will be ignored in hints if
FI_SOURCE flag is set. On output a provider shall return an address that
corresponds to the indicated fabric, domain, node, and/or service fields. The
format of the address is indicated by the returned addr_format field. Note that
any returned address is only used when opening a local endpoint. The address is
not guaranteed to be usable by a peer process.
dest_addr - destination address
If specified, indicates the destination address. This field will be ignored in
hints unless the node and service parameters are NULL or FI_SOURCE flag is set. If
FI_SOURCE is not specified, on output a provider shall return an address the
corresponds to the indicated node and/or service fields, relative to the fabric and
domain. Note that any returned address is only usable locally.
handle - provider context handle
The use of this field is operation specific. If hints->handle is set to struct
fid_pep, the hints->handle will be copied to info->handle on output from
fi_getinfo. Other values of hints->handle will be handled in a provider specific
manner. The fi_info::handle field is also used by fi_endpoint() and fi_reject()
calls when processing connection requests or to inherit another endpoint's
attributes. See fi_eq(3), fi_reject(3), and fi_endpoint(3). The info->handle
field will be ignored by fi_dupinfo and fi_freeinfo.
tx_attr - transmit context attributes
Optionally supplied transmit context attributes. Transmit context attributes may
be specified and returned as part of fi_getinfo. When provided as hints, requested
values of struct fi_tx_ctx_attr should be set. On output, the actual transmit
context attributes that can be provided will be returned. Output values will be
greater than or equal to the requested input values.
rx_attr - receive context attributes
Optionally supplied receive context attributes. Receive context attributes may be
specified and returned as part of fi_getinfo. When provided as hints, requested
values of struct fi_rx_ctx_attr should be set. On output, the actual receive
context attributes that can be provided will be returned. Output values will be
greater than or or equal to the requested input values.
ep_attr - endpoint attributes
Optionally supplied endpoint attributes. Endpoint attributes may be specified and
returned as part of fi_getinfo. When provided as hints, requested values of struct
fi_ep_attr should be set. On output, the actual endpoint attributes that can be
provided will be returned. Output values will be greater than or equal to
requested input values. See fi_endpoint(3) for details.
domain_attr - domain attributes
Optionally supplied domain attributes. Domain attributes may be specified and
returned as part of fi_getinfo. When provided as hints, requested values of struct
fi_domain_attr should be set. On output, the actual domain attributes that can be
provided will be returned. Output values will be greater than or equal to
requested input values. See fi_domain(3) for details.
fabric_attr - fabric attributes
Optionally supplied fabric attributes. Fabric attributes may be specified and
returned as part of fi_getinfo. When provided as hints, requested values of struct
fi_fabric_attr should be set. On output, the actual fabric attributes that can be
provided will be returned. See fi_fabric(3) for details.
nic - network interface details
Optional attributes related to the hardware NIC associated with the specified
fabric, domain, and endpoint data. This field is only valid for providers where
the corresponding attributes are closely associated with a hardware NIC. See
fi_nic(3) for details.
CAPABILITIES
Interface capabilities are obtained by OR-ing the following flags together. If
capabilities in the hint parameter are set to 0, the underlying provider will return the
set of capabilities which are supported. Otherwise, providers will return data matching
the specified set of capabilities. Providers may indicate support for additional
capabilities beyond those requested when the use of expanded capabilities will not
adversely affect performance or expose the application to communication beyond that which
was requested. Applications may use this feature to request a minimal set of
requirements, then check the returned capabilities to enable additional optimizations.
FI_ATOMIC
Specifies that the endpoint supports some set of atomic operations. Endpoints
supporting this capability support operations defined by struct fi_ops_atomic. In
the absence of any relevant flags, FI_ATOMIC implies the ability to initiate and be
the target of remote atomic reads and writes. Applications can use the FI_READ,
FI_WRITE, FI_REMOTE_READ, and FI_REMOTE_WRITE flags to restrict the types of atomic
operations supported by an endpoint.
FI_COLLECTIVE
Requests support for collective operations. Endpoints that support this capability
support the collective operations defined in fi_collective(3).
FI_DIRECTED_RECV
Requests that the communication endpoint use the source address of an incoming
message when matching it with a receive buffer. If this capability is not set,
then the src_addr parameter for msg and tagged receive operations is ignored.
FI_FENCE
Indicates that the endpoint support the FI_FENCE flag on data transfer operations.
Support requires tracking that all previous transmit requests to a specified remote
endpoint complete prior to initiating the fenced operation. Fenced operations are
often used to enforce ordering between operations that are not otherwise guaranteed
by the underlying provider or protocol.
FI_HMEM
Specifies that the endpoint should support transfers to and from device memory.
FI_LOCAL_COMM
Indicates that the endpoint support host local communication. This flag may be
used in conjunction with FI_REMOTE_COMM to indicate that local and remote
communication are required. If neither FI_LOCAL_COMM or FI_REMOTE_COMM are
specified, then the provider will indicate support for the configuration that
minimally affects performance. Providers that set FI_LOCAL_COMM but not
FI_REMOTE_COMM, for example a shared memory provider, may only be used to
communication between processes on the same system.
FI_MSG Specifies that an endpoint should support sending and receiving messages or
datagrams. Message capabilities imply support for send and/or receive queues.
Endpoints supporting this capability support operations defined by struct
fi_ops_msg.
The caps may be used to specify or restrict the type of messaging operations that are
supported. In the absence of any relevant flags, FI_MSG implies the ability to send and
receive messages. Applications can use the FI_SEND and FI_RECV flags to optimize an
endpoint as send-only or receive-only.
FI_MULTICAST
Indicates that the endpoint support multicast data transfers. This capability must
be paired with FI_MSG. Applications can use FI_SEND and FI_RECV to optimize
multicast as send-only or receive-only.
FI_MULTI_RECV
Specifies that the endpoint must support the FI_MULTI_RECV flag when posting
receive buffers.
FI_NAMED_RX_CTX
Requests that endpoints which support multiple receive contexts allow an initiator
to target (or name) a specific receive context as part of a data transfer
operation.
FI_READ
Indicates that the user requires an endpoint capable of initiating reads against
remote memory regions. This flag requires that FI_RMA and/or FI_ATOMIC be set.
FI_RECV
Indicates that the user requires an endpoint capable of receiving message data
transfers. Message transfers include base message operations as well as tagged
message functionality.
FI_REMOTE_COMM
Indicates that the endpoint support communication with endpoints located at remote
nodes (across the fabric). See FI_LOCAL_COMM for additional details. Providers
that set FI_REMOTE_COMM but not FI_LOCAL_COMM, for example NICs that lack loopback
support, cannot be used to communicate with processes on the same system.
FI_REMOTE_READ
Indicates that the user requires an endpoint capable of receiving read memory
operations from remote endpoints. This flag requires that FI_RMA and/or FI_ATOMIC
be set.
FI_REMOTE_WRITE
Indicates that the user requires an endpoint capable of receiving write memory
operations from remote endpoints. This flag requires that FI_RMA and/or FI_ATOMIC
be set.
FI_RMA Specifies that the endpoint should support RMA read and write operations.
Endpoints supporting this capability support operations defined by struct
fi_ops_rma. In the absence of any relevant flags, FI_RMA implies the ability to
initiate and be the target of remote memory reads and writes. Applications can use
the FI_READ, FI_WRITE, FI_REMOTE_READ, and FI_REMOTE_WRITE flags to restrict the
types of RMA operations supported by an endpoint.
FI_RMA_EVENT
Requests that an endpoint support the generation of completion events when it is
the target of an RMA and/or atomic operation. This flag requires that
FI_REMOTE_READ and/or FI_REMOTE_WRITE be enabled on the endpoint.
FI_RMA_PMEM
Indicates that the provider is 'persistent memory aware' and supports RMA
operations to and from persistent memory. Persistent memory aware providers must
support registration of memory that is backed by non- volatile memory, RMA
transfers to/from persistent memory, and enhanced completion semantics. This flag
requires that FI_RMA be set. This capability is experimental.
FI_SEND
Indicates that the user requires an endpoint capable of sending message data
transfers. Message transfers include base message operations as well as tagged
message functionality.
FI_SHARED_AV
Requests or indicates support for address vectors which may be shared among
multiple processes.
FI_SOURCE
Requests that the endpoint return source addressing data as part of its completion
data. This capability only applies to connectionless endpoints. Note that
returning source address information may require that the provider perform address
translation and/or look-up based on data available in the underlying protocol in
order to provide the requested data, which may adversely affect performance. The
performance impact may be greater for address vectors of type FI_AV_TABLE.
FI_SOURCE_ERR
Must be paired with FI_SOURCE. When specified, this requests that raw source
addressing data be returned as part of completion data for any address that has not
been inserted into the local address vector. Use of this capability may require
the provider to validate incoming source address data against addresses stored in
the local address vector, which may adversely affect performance.
FI_TAGGED
Specifies that the endpoint should handle tagged message transfers. Tagged message
transfers associate a user-specified key or tag with each message that is used for
matching purposes at the remote side. Endpoints supporting this capability support
operations defined by struct fi_ops_tagged. In the absence of any relevant flags,
FI_TAGGED implies the ability to send and receive tagged messages. Applications
can use the FI_SEND and FI_RECV flags to optimize an endpoint as send-only or
receive-only.
FI_TRIGGER
Indicates that the endpoint should support triggered operations. Endpoints support
this capability must meet the usage model as described by fi_trigger.3.
FI_VARIABLE_MSG
Requests that the provider must notify a receiver when a variable length message is
ready to be received prior to attempting to place the data. Such notification will
include the size of the message and any associated message tag (for FI_TAGGED).
See 'Variable Length Messages' in fi_msg.3 for full details. Variable length
messages are any messages larger than an endpoint configurable size. This flag
requires that FI_MSG and/or FI_TAGGED be set.
FI_WRITE
Indicates that the user requires an endpoint capable of initiating writes against
remote memory regions. This flag requires that FI_RMA and/or FI_ATOMIC be set.
Capabilities may be grouped into three general categories: primary, secondary, and primary
modifiers. Primary capabilities must explicitly be requested by an application, and a
provider must enable support for only those primary capabilities which were selected.
Primary modifiers are used to limit a primary capability, such as restricting an endpoint
to being send-only. If no modifiers are specified for an applicable capability, all
relevant modifiers are assumed. See above definitions for details.
Secondary capabilities may optionally be requested by an application. If requested, a
provider must support the capability or fail the fi_getinfo request (FI_ENODATA). A
provider may optionally report non-selected secondary capabilities if doing so would not
compromise performance or security.
Primary capabilities: FI_MSG, FI_RMA, FI_TAGGED, FI_ATOMIC, FI_MULTICAST, FI_NAMED_RX_CTX,
FI_DIRECTED_RECV, FI_VARIABLE_MSG, FI_HMEM, FI_COLLECTIVE
Primary modifiers: FI_READ, FI_WRITE, FI_RECV, FI_SEND, FI_REMOTE_READ, FI_REMOTE_WRITE
Secondary capabilities: FI_MULTI_RECV, FI_SOURCE, FI_RMA_EVENT, FI_SHARED_AV, FI_TRIGGER,
FI_FENCE, FI_LOCAL_COMM, FI_REMOTE_COMM, FI_SOURCE_ERR, FI_RMA_PMEM.
MODE
The operational mode bits are used to convey requirements that an application must adhere
to when using the fabric interfaces. Modes specify optimal ways of accessing the reported
endpoint or domain. Applications that are designed to support a specific mode of
operation may see improved performance when that mode is desired by the provider. It is
recommended that providers support applications that disable any provider preferred modes.
On input to fi_getinfo, applications set the mode bits that they support. On output,
providers will clear mode bits that are not necessary to achieve high-performance. Mode
bits that remain set indicate application requirements for using the fabric interfaces
created using the returned fi_info. The set of modes are listed below. If a NULL hints
structure is provided, then the provider's supported set of modes will be returned in the
info structure(s).
FI_ASYNC_IOV
Applications can reference multiple data buffers as part of a single operation
through the use of IO vectors (SGEs). Typically, the contents of an IO vector are
copied by the provider into an internal buffer area, or directly to the underlying
hardware. However, when a large number of IOV entries are supported, IOV buffering
may have a negative impact on performance and memory consumption. The FI_ASYNC_IOV
mode indicates that the application must provide the buffering needed for the IO
vectors. When set, an application must not modify an IO vector of length > 1,
including any related memory descriptor array, until the associated operation has
completed.
FI_BUFFERED_RECV
The buffered receive mode bit indicates that the provider owns the data buffer(s)
that are accessed by the networking layer for received messages. Typically, this
implies that data must be copied from the provider buffer into the application
buffer. Applications that can handle message processing from network allocated
data buffers can set this mode bit to avoid copies. For full details on
application requirements to support this mode, see the 'Buffered Receives' section
in fi_msg(3). This mode bit applies to FI_MSG and FI_TAGGED receive operations.
FI_CONTEXT
Specifies that the provider requires that applications use struct fi_context as
their per operation context parameter for operations that generated full
completions. This structure should be treated as opaque to the application. For
performance reasons, this structure must be allocated by the user, but may be used
by the fabric provider to track the operation. Typically, users embed struct
fi_context within their own context structure. The struct fi_context must remain
valid until the corresponding operation completes or is successfully canceled. As
such, fi_context should NOT be allocated on the stack. Doing so is likely to
result in stack corruption that will be difficult to debug. Users should not
update or interpret the fields in this structure, or reuse it until the original
operation has completed. If an operation does not generate a completion (i.e. the
endpoint was configured with FI_SELECTIVE_COMPLETION and the operation was not
initiated with the FI_COMPLETION flag) then the context parameter is ignored by the
fabric provider. The structure is specified in rdma/fabric.h.
FI_CONTEXT2
This bit is similar to FI_CONTEXT, but doubles the provider's requirement on the
size of the per context structure. When set, this specifies that the provider
requires that applications use struct fi_context2 as their per operation context
parameter. Or, optionally, an application can provide an array of two fi_context
structures (e.g. struct fi_context[2]) instead. The requirements for using struct
fi_context2 are identical as defined for FI_CONTEXT above.
FI_LOCAL_MR
The provider is optimized around having applications register memory for locally
accessed data buffers. Data buffers used in send and receive operations and as the
source buffer for RMA and atomic operations must be registered by the application
for access domains opened with this capability. This flag is defined for
compatibility and is ignored if the application version is 1.5 or later and the
domain mr_mode is set to anything other than FI_MR_BASIC or FI_MR_SCALABLE. See
the domain attribute mr_mode fi_domain(3) and fi_mr(3).
FI_MSG_PREFIX
Message prefix mode indicates that an application will provide buffer space in
front of all message send and receive buffers for use by the provider. Typically,
the provider uses this space to implement a protocol, with the protocol headers
being written into the prefix area. The contents of the prefix space should be
treated as opaque. The use of FI_MSG_PREFIX may improve application performance
over certain providers by reducing the number of IO vectors referenced by
underlying hardware and eliminating provider buffer allocation.
FI_MSG_PREFIX only applies to send and receive operations, including tagged sends and
receives. RMA and atomics do not require the application to provide prefix buffers.
Prefix buffer space must be provided with all sends and receives, regardless of the size
of the transfer or other transfer options. The ownership of prefix buffers is treated the
same as the corresponding message buffers, but the size of the prefix buffer is not
counted toward any message limits, including inject.
Applications that support prefix mode must supply buffer space before their own message
data. The size of space that must be provided is specified by the msg_prefix_size
endpoint attribute. Providers are required to define a msg_prefix_size that is a multiple
of 8 bytes. Additionally, applications may receive provider generated packets that do not
contain application data. Such received messages will indicate a transfer size of that is
equal to or smaller than msg_prefix_size.
The buffer pointer given to all send and receive operations must point to the start of the
prefix region of the buffer (as opposed to the payload). For scatter-gather send/recv
operations, the prefix buffer must be a contiguous region, though it may or may not be
directly adjacent to the payload portion of the buffer.
FI_NOTIFY_FLAGS_ONLY
This bit indicates that general completion flags may not be set by the provider,
and are not needed by the application. If specified, completion flags which simply
report the type of operation that completed (e.g. send or receive) may not be set.
However, completion flags that are used for remote notifications will still be set
when applicable. See fi_cq(3) for details on which completion flags are valid when
this mode bit is enabled.
FI_RESTRICTED_COMP
This bit indicates that the application will only share completion queues and
counters among endpoints, transmit contexts, and receive contexts that have the
same set of capability flags.
FI_RX_CQ_DATA
This mode bit only applies to data transfers that set FI_REMOTE_CQ_DATA. When set,
a data transfer that carries remote CQ data will consume a receive buffer at the
target. This is true even for operations that would normally not consume posted
receive buffers, such as RMA write operations.
ADDRESSING FORMATS
Multiple fabric interfaces take as input either a source or destination address parameter.
This includes struct fi_info (src_addr and dest_addr), CM calls (getname, getpeer,
connect, join, and leave), and AV calls (insert, lookup, and straddr). The fi_info
addr_format field indicates the expected address format for these operations.
A provider may support one or more of the following addressing formats. In some cases, a
selected addressing format may need to be translated or mapped into an address which is
native to the fabric. See fi_av(3).
FI_ADDR_BGQ
Address is an IBM proprietary format that is used with their Blue Gene Q systems.
FI_ADDR_EFA
Address is an Amazon Elastic Fabric Adapter (EFA) proprietary format.
FI_ADDR_GNI
Address is a Cray proprietary format that is used with their GNI protocol.
FI_ADDR_PSMX
Address is an Intel proprietary format used with their Performance Scaled Messaging
protocol.
FI_ADDR_PSMX2
Address is an Intel proprietary format used with their Performance Scaled Messaging
protocol version 2.
FI_ADDR_STR
Address is a formatted character string. The length and content of the string is
address and/or provider specific, but in general follows a URI model:
address_format[://[node][:[service][/[field3]...][?[key=value][&k2=v2]...]]]
Examples: - fi_sockaddr://10.31.6.12:7471 - fi_sockaddr_in6://[fe80::6:12]:7471 -
fi_sockaddr://10.31.6.12:7471?qos=3
Since the string formatted address does not contain any provider information, the
prov_name field of the fabric attribute structure should be used to filter by provider if
necessary.
FI_FORMAT_UNSPEC
FI_FORMAT_UNSPEC indicates that a provider specific address format should be
selected. Provider specific addresses may be protocol specific or a vendor
proprietary format. Applications that select FI_FORMAT_UNSPEC should be prepared
to treat returned addressing data as opaque. FI_FORMAT_UNSPEC targets apps which
make use of an out of band address exchange. Applications which use
FI_FORMAT_UNSPEC may use fi_getname() to obtain a provider specific address
assigned to an allocated endpoint.
FI_SOCKADDR
Address is of type sockaddr. The specific socket address format will be determined
at run time by interfaces examining the sa_family field.
FI_SOCKADDR_IB
Address is of type sockaddr_ib (defined in Linux kernel source)
FI_SOCKADDR_IN
Address is of type sockaddr_in (IPv4).
FI_SOCKADDR_IN6
Address is of type sockaddr_in6 (IPv6).
FI_ADDR_PSMX
Address is an Intel proprietary format that is used with their PSMX (extended
performance scaled messaging) protocol.
FLAGS
The operation of the fi_getinfo call may be controlled through the use of input flags.
Valid flags include the following.
FI_NUMERICHOST
Indicates that the node parameter is a numeric string representation of a fabric
address, such as a dotted decimal IP address. Use of this flag will suppress any
lengthy name resolution protocol.
FI_PROV_ATTR_ONLY
Indicates that the caller is only querying for what providers are potentially
available. All providers will return exactly one fi_info struct, regardless of
whether that provider is usable on the current platform or not. The returned
fi_info struct will contain default values for all members, with the exception of
fabric_attr. The fabric_attr member will have the prov_name and prov_version
values filled in.
FI_SOURCE
Indicates that the node and service parameters specify the local source address to
associate with an endpoint. If specified, either the node and/or service parameter
must be non-NULL. This flag is often used with passive endpoints.
RETURN VALUE
fi_getinfo() returns 0 on success. On error, fi_getinfo() returns a negative value
corresponding to fabric errno. Fabric errno values are defined in rdma/fi_errno.h.
fi_allocinfo() returns a pointer to a new fi_info structure on success, or NULL on error.
fi_dupinfo() duplicates a single fi_info structure and all the substructures within it,
returning a pointer to the new fi_info structure on success, or NULL on error. Both calls
require that the returned fi_info structure be freed via fi_freeinfo().
ERRORS
FI_EBADFLAGS
The specified endpoint or domain capability or operation flags are invalid.
FI_ENODATA
Indicates that no providers could be found which support the requested fabric
information.
FI_ENOMEM
Indicates that there was insufficient memory to complete the operation.
NOTES
If hints are provided, the operation will be controlled by the values that are supplied in
the various fields (see section on fi_info). Applications that require specific
communication interfaces, domains, capabilities or other requirements, can specify them
using fields in hints. Libfabric returns a linked list in info that points to a list of
matching interfaces. info is set to NULL if there are no communication interfaces or none
match the input hints.
If node is provided, fi_getinfo will attempt to resolve the fabric address to the given
node. If node is not provided, fi_getinfo will attempt to resolve the fabric addressing
information based on the provided hints. The caller must call fi_freeinfo to release
fi_info structures returned by fi_getinfo.
If neither node, service or hints are provided, then fi_getinfo simply returns the list
all available communication interfaces.
Multiple threads may call fi_getinfo simultaneously, without any requirement for
serialization.
SEE ALSO
fi_open(3), fi_endpoint(3), fi_domain(3), fi_nic(3)
AUTHORS
OpenFabrics.