[ofiwg] getting hardware details from libfabric

[Hefty, Sean]

This is an initial proposal:

The device attributes are per fi_info structure (which includes the network address, domain, and ep attributes).  The app does not need to open any resources to obtain the data.


When fi_getinfo() is called with FI_DEVICE_ATTR flag set, each fi_info::handle will reference a struct fid_attr, if valid.


// Definition of struct fid_attr.  Field types could change.
struct fid_attr {
	struct fid;  /* fclass = FI_TYPE_DEVICE_ATTR */
	struct dev_attr {
		char *interface;
		char *device_id;
		char *device_version;
		char *vendor_id;
		char *firmware;
	};
	struct bus_attr {
		char *domain_id; 
		char *bus_id;
		char *device_id;
		char *function_id;
	};
	struct link_attr {
		char *address;
		size_t mtu;
		enum fi_link_state state; /* up, down, unknown */
		char *protocol;
		size_t speed; /* bits per second */
	};
	struct prov_attr {
		size_t size;
		char data[];
	};
};


The prov_attr structure can be cast to a provider specific structure (e.g. usnic_devinfo) if the app knows the structure format.  I would add a new public header for all definitions.  Additionally, fi_tostr() can be used to display the attributes.  fid_attr allows fi_tostr() to route the call to the provider to handle the prov_attr portion (done using new fi_control FI_TOSTR option).

I'm still debating whether fi_freeinfo() will free fid_attr, or if the app must call fi_close() separately.

- Sean