fi_provider(3) Libfabric Programmer's Manual
NAME
fi_prov_ini - External provider entry point
- fi_param_define / fi_param_get
- Register and retrieve environment variables with the libfabric core
- fi_log_enabled / fi_log
- Control and output debug logging information.
- fi_open / fi_close
- Open a named library object
- fi_export_fid / fi_import_fid
- Share a fabric object between different providers or resources
SYNOPSIS
#include <rdma/fabric.h>
#include <rdma/prov/fi_prov.h>
struct fi_provider* fi_prov_ini(void);
int fi_param_define(const struct fi_provider *provider, const char *param_name,
enum fi_param_type type, const char *help_string_fmt, ...);
int fi_param_get_str(struct fi_provider *provider, const char *param_name,
char **value);
int fi_param_get_int(struct fi_provider *provider, const char *param_name,
int *value);
int fi_param_get_bool(struct fi_provider *provider, const char *param_name,
int *value);
int fi_param_get_size_t(struct fi_provider *provider, const char *param_name,
size_t *value);
#include <rdma/fabric.h>
#include <rdma/prov/fi_prov.h>
#include <rdma/prov/fi_log.h>
int fi_log_enabled(const struct fi_provider *prov, enum fi_log_level level,
enum fi_log_subsys subsys);
void fi_log(const struct fi_provider *prov, enum fi_log_level level,
enum fi_log_subsys subsys, const char *func, int line,
const char *fmt, ...);
#include <rdma/fabric.h>
int fi_open(uint32_t version, const char *name, void *attr,
size_t attr_len, uint64_t flags, struct fid **fid, void *context);
int fi_close(struct fid *fid);
#include <rdma/fabric.h>
#include <rdma/fi_ext.h>
int fi_export_fid(struct fid *fid, uint64_t flags,
struct fid **expfid, void *context);
int fi_import_fid(struct fid *fid, struct fid *expfid, uint64_t flags);
ARGUMENTS
- provider
- Reference to the provider.
- version
- API version requested by application.
- name
- Well-known name of the library object to open.
- attr
- Optional attributes of object to open.
- attr_len
- Size of any attribute structure passed to fi_open. Should be 0 if no attributes are give.
- fid
- Returned fabric identifier for opened object.
DESCRIPTION
A fabric provider implements the application facing software interfaces needed to access network specific protocols, drivers, and hardware. The interfaces and structures defined by this man page are exported by the libfabric library, but are targeted for provider implementations, rather than for direct use by most applications.
Integrated providers are those built directly into the libfabric library itself. External providers are loaded dynamically by libfabric at initialization time. External providers must be in a standard library path or in the libfabric library search path as specified by environment variable. Additionally, external providers must be named with the suffix “-fi.so” at the end of the name.
Named objects are special purpose resources which are accessible directly to applications. They may be used to enhance or modify the behavior of library core. For details, see the fi_open call below.
fi_prov_ini
This entry point must be defined by external providers. On loading, libfabric will invoke fi_prov_ini() to retrieve the provider’s fi_provider structure. Additional interactions between the libfabric core and the provider will be through the interfaces defined by that struct.
fi_param_define
Defines a configuration parameter for use by a specified provider. The help_string and param_name arguments must be non-NULL, help_string must additionally be non-empty. They are copied internally and may be freed after calling fi_param_define.
fi_param_get
Gets the value of a configuration parameter previously defined using
fi_param_define(). The value comes from the environment variable name of
the form FI_
If the parameter was previously defined and the user set a value, FI_SUCCESS is returned and (*value) points to the retrieved value.
If the parameter name was previously defined, but the user did not set a value, -FI_ENODATA is returned and the value of (*value) is unchanged.
If the parameter name was not previously defined via fi_param_define(), -FI_ENOENT will be returned and the value of (*value) is unchanged.
If the value in the environment is not valid for the parameter type, -FI_EINVAL will be returned and the value of (*value) is unchanged.
fi_log_enabled / fi_log
TODO
fi_open
Open a library resource using a well-known name. This feature allows applications and providers a mechanism which can be used to modify or enhance core library services and behavior. The details are specific based on the requested object name. Most applications will not need this level of control.
The library API version known to the application should be provided through the version parameter. The use of attributes is object dependent. If required, attributes should be provided through the attr parameter, with attr_len set to the size of the referenced attribute structure. The following is a list of published names, along with descriptions of the service or resource to which they correspond.
- mr_cache
- The mr_cache object references the internal memory registration cache
used by the different providers. Additional information on the cache
is available in the
fi_mr(3)man page.
fi_export_fid / fi_import_fid
Generally, fabric objects are allocated and managed entirely by a single provider. Typically only the application facing software interfaces of a fabric object are defined, for example, the message or tagged operations of an endpoint. The fi_export_fid and fi_import_fid calls provide a a mechanism by which provider facing APIs may be accessed. This allows the creation of fid objects that are shareable between providers, or for library plug-in services. The ability to export a shareable object is object and provider implementation dependent.
Shareable fids typically contain at least 3 main components: a base fid, a set of exporter defined ops, and a set of importer defined ops.
NOTES
TODO
PROVIDER INTERFACE
The fi_provider structure defines entry points for the libfabric core to use to access the provider. All other calls into a provider are through function pointers associated with allocated objects.
struct fi_provider {
uint32_t version;
uint32_t fi_version;
struct fi_context context;
const char *name;
int (*getinfo)(uint32_t version, const char *node, const char *service,
uint64_t flags, const struct fi_info *hints,
struct fi_info **info);
int (*fabric)(struct fi_fabric_attr *attr, struct fid_fabric **fabric,
void *context);
void (*cleanup)(void);
};
version
The provider version. For providers integrated with the library, this is often the same as the library version.
fi_version
The library interface version that the provider was implemented against. The provider’s fi_version must be greater than or equal to an application’s requested api version for the application to use the provider. It is a provider’s responsibility to support older versions of the api if it wishes to supports legacy applications. For integrated providers
TODO
RETURN VALUE
Returns FI_SUCCESS on success. On error, a negative value corresponding to
fabric errno is returned. Fabric errno values are defined in
rdma/fi_errno.h.