fi_profile - Man Page

fi_profile — Fabric Profiling Interfeace

fi_profile_open / fi_profile_close

Open/close a profile object on an endpoint or a domain specified by the fid or associated with the profile object.

fi_profile_query_vars / fi_profile_query_events

Query available profiling variables/events associated the profile object.

fi_profile_read_u64

Read the value of a FI_UINT64-typed variable.

fi_profile_reg_callback

Register a callback function to a profiling event.

fi_profile_start_reads / fi_profile_end_reads

Control consecutively accessing on multiple variables at the same time.

include <rdma/fi_profile.h>

int fi_profile_open(struct fid *fid, uint64_t flags,
    struct fid_profile **prof_fid, void *context);

int fi_profile_close(struct fid_profile *prof_fid);

void fi_profile_reset(struct fid_profile *prof_fid,  uint64_t flags);

ssize_t fi_profile_query_vars(struct fid_profile *prof_fid,
    struct fi_profile_desc *varlist, size_t *count)

ssize_t fi_profile_query_events(struct fid_profile *prof_fid,
    struct fi_profile_desc *eventlist, size_t *count);

int fi_profile_register_callback(struct fid_profile *prof_fid,
    uint32_t event_id,
    int (*callback)(struct fid_profile *prof_fid, 
                    struct fi_profile_desc *event, void *param, 
                    size_t size, void *context),
    void *context);

sszie_t fi_profile_read_u64(struct fid_profile *prof_fid, uint32_t var_id,
    uint64_t *data);

void fi_profile_start_reads(struct fid_profile *prof_fid, uint64_t flags);

void fi_profile_end_reads(struct fid_profile *prof_fid, uint64_t flags);

fid

Reference to an endpoint or a domain which is the target for profiling.

prof_fid

Reference to a profile object associating with the target fid.

flags

Flags to control profiling or operation.

context

Context associated with the profiling operations.

varlist

An array of profiling variables.

eventlist

An array of profiling events.

count

Number of variables or events available in the provider.

var_id

An unique ID for a variable.

event_id

An unique ID for an event.

callback

Callback function registered for an event. See below callback description.

data

The current value of a variable.

Fabric profiling interface allows users to obtain configuration or runtime properties from the providers in the form of “variables”. Providers define variables and make them readable to users through the profiling interface. Providers define events and use them to report when an operation has occurred or a state changed where one or more variables may change their values. Users can register callback functions to one or more events, and receive notifications from providers once an event occurs.

To support the profiling interface, an endpoint or a domain in a provider needs to maintain a fid_profile object, and implement the profiling operations there. To start a profiling, an open call must be made on the target endpoint or domain object to obtain the fid_profile object. If the target object does not support profiling, the open call will fail with the error code -FI_ENOSYS. Once a fid_profile object is obtained successfully, it can be used to query available variables or events and read variables’ values.

The profiling variables are defined in providers and are accessible through the profiling interface. Variables are specified using struct fi_profile_desc described below. A variable can be a configuration setting, a runtime state, or a counter associated with an endpoint or a domain. Some variables are common and available in most providers, while others are provider-specific and are only available in one provider. Users can query available variables and their values using the profiling interface.

Provider specific variables are outside the scope of this man page. libfabric defined variables and their datatypes are described below.

Profiling events are defined to notify users that an operation has occurred or the state of an object has changed, which typically indicate that one or more variables have been modified. Events are specified using struct fi_profile_desc described below. Similar to variables, events may be pre-defined by libfabric or be provider specific. Users can register a callback to be notified when an event occurs. libfabric defined events and the data that corresponds with the event, if any, are described below.

Applications may read variables’ values from the event callback when allowed, but may not register or unregister for events, query for profiling variables or events.

libfarbic pre-defined events include:

Variables and events are described using struct fi_profile_desc:

enum fi_profile_type {
    fi_primitive_type,
    fi_defined_type,
};

struct fi_profile_desc {
    uint32_t id;
    enum fi_profile_type datatype_sel;
    union {
        enum fi_datatype primitive;
        enum fi_type defined;
    } datatype;
    uint64_t flags;
    size_t size;
    const char *name;
    const char *desc;
};

fi_profile_open is used to initiate a profiling on a target endpoint or domain specified by the fid. Upon retuning successfully, a fid_profile is returned and can be used to perform profiling operations. If the target endpoint or domain does not support fabric profiling interface, the open call will fail with error code -FI_ENOSYS.

Close the profiling operations and release related resources.

fi_profile_query_vars and fi_profile_query_events calls can be used to query available variables or events from the target endpoint or domain associated with the profile object. On input, the buffer (“varlist” or “eventlist”) should be allocated, and the “count” indicates the maximum number of entries (variables or events) allowed in the buffer. On output, the “count” indicates the actual number of varibles or events available in the target endpoint or domain. If the buffer is NULL, only the “count” will be set and return. User can use the “count” to allocate space and call the function again. The return value of these calls indicates the number of entries returned the buffer.

fi_profile_reg_callback registers a callback function to the event. The event should be in the event list obtained using the fi_profile_query_events, otherwise, an error code -FI_EINVAL will be returned.

int (*callback)(struct fid_profile *prof_fid, struct fi_profile_desc *event,
                void *param, size_t size, void *context)

fi_profile_read_u64 is a wrapper function for FI_UINT64-type variables. It returns an uint64_t value of the specified variable. The variable should be in the variable list obtained using fi_profile_query_vars, otherwise, an error code -FI_EINVAL will be returned.

fi_profile_start_reads and fi_profile_end_reads calls are used when trying to read multiple variables at the same time. Variables read in between these two calls are expected to have values from a single snapshot.

Users should call fi_profile_close to release all resources allocated for profiling in the provider.

Returns 0 on success. On error, a negative value corresponding to fabric errno is returned. If the provider does not support profiling interface, a -FI_ENOSYS will be returned. For fi_profile_query_vars and fi_profile_query_events, a positive return value indicates the number of variables or events returned in the list.

Fabric errno values are defined in rdma/fi_errno.h.

OpenFabrics.