[ewg] librdmacm 1.0.12 release notes for OFED 1.5.2

[Hefty, Sean]

Here is the first cut at release notes -- attached and inline -- for the OFED 1.5.2 release of the librdmacm.

- Sean

---

librdmacm release notes
-----------------------
Several enhancements were added to librdmacm release 1.0.12 that
are intended to simplify using RDMA devices and address scalability issues.
These changes were in response to long standing requests to make
connection establishment 'more like sockets'.  For full details,
users should refer to the appropriate man pages.  Major changes include:


* Support synchronous operation for library calls.  Users can control
  whether an rdma_cm_id operates asynchronously or synchronously based on
  the rdma_event_channel parameter.  Use of synchronous operations
  reduces the amount of application code required to use the librdmacm
  by eliminating the need for event processing code.

  An rdma_cm_id will be marked for synchronous operation if the
  rdma_event_channel parameter is NULL for rdma_create_id or
  rdma_migrate_id.  Users can toggle between synchronous and
  asynchronous operation through the rdma_migrate_id call.

  Calls that operate synchronously include rdma_resolve_addr,
  rdma_resolve_route, rdma_connect, rdma_accept, and rdma_get_request.
  Synchronous event data is returned to the user through the
  rdma_cm_id.


* The addition of a new API: rdma_getaddrinfo.  This call is modeled
  after getaddrinfo, but for RDMA devices and connections.  It has the
  following notable deviations from getaddrinfo:

  A source address is returned as part of the call to allow the
  user to allocate necessary local HW resources for connections.

  Optional routing information may be returned to support
  Infiniband fabrics.  IB routing information includes necessary
  path record data.  rdma_getaddrinfo will obtain this information
  if IB ACM support (see below) is enabled.  The use of IB ACM
  is not required for rdma_getaddrinfo.

  rdma_getaddrinfo provides future extensions to support
  more complex address and route resolution mechanisms, such as
  multiple path support and failover.


* Support for a new APIs: rdma_get_request, rdma_create_ep, and
  rdma_destroy_ep.  rdma_get_request simplifies the passive side
  implementation by adding synchronous support for accepting new
  connections.  rdma_create_ep combines the functionality of
  rdma_create_id, rdma_create_qp, rdma_resolve_addr, and rdma_resolve_route
  in a single API that uses the output of rdma_getaddrinfo as its input.

  
* Support for optional parameters.  To simplify support for casual RDMA
  developers and researchers, the librdmacm can allocate protection
  domains, completion queues, and queue pairs on a user's behalf.
  This simplifies the amount of information that a developer
  must learn in order to use RDMA, plus allows the user to take
  advantage of higher-level completion processing abstractions.

  In addition to optional parameters, a user can also specify that the
  librdmacm should automatically select usable values for RDMA read
  operations.


* Add support for IB ACM.  IB ACM (InfiniBand Assistant for Communication
  Management) defines a socket based protocol to an IB address and route
  resolution service.  One implementation of that service is provided
  separately by the ibacm package, but anyone can implement the service
  provided that they adhere to the IB ACM socket protocol.  IB ACM is an
  experimental service targeted at increasing the scalability of applications
  running on a large cluster.
  
  Use of IB ACM is not required and is controlled through the build option
  '--with-ib_acm'.  If the librdmacm fails to contact the IB ACM service, it
  reverts to using kernel services to resolve address and routing data.


* Add RDMA helper routines.  The librdmacm provide a set of simpler verbs
  calls for posting work requests, registering memory, and checking for
  completions.  These calls are wrappers around libibverbs routines.



-------------- next part --------------
A non-text attachment was scrubbed...
Name: rel-notes
Type: application/octet-stream
Size: 3836 bytes
Desc: rel-notes
URL: <http://lists.openfabrics.org/pipermail/ewg/attachments/20100608/91e6901f/attachment.obj>