NEWS-ptg

2020-12-22

 - Add PTG CUDA bodies support for:
      - User-defined stage_in/stage_out routines for data transfers.
      - User-defined size of buffers allocated on the GPU memory.
      - Data collection for which the flow logically belongs to, enables
         user-defined stage in/out routines to rely on the data collection
         to get info necessary for the transfer.
      BODY [type=CUDA
         stage_in=< user routine >
         stage_in=< user routine >
         < flowname >.size=< bytes to be reserve on GPU >
         < flowname >.dc=< datacollection for this flow >]

 - PaRSEC data copies are described by a type.
   Set up by data collection when accessing data or when creating temporary
   copies.

 - Change PTG typing of dependencies to specify datatype used to send/receive
   data between remote peers using the keyword [type_remote =...]
         TASK_A: A -> B TASK_B [type_remote = t1]
         TASK_B: B <- A TASK_A [type_remote = t2]
   * Data is sent with type_remote on the output dependency of the sender and
     received on the receiver using the type_remote on the input dependency.
   * If no types are specified, data is sent using the data copy type and
     received using the default type of the taskpool arena.

 - PTG supports reshaping of datacopies (type conversion):
   * During accesses to data collections:
      - Reading from matrix: A <- desc(m, n) [type =... type_data=...]
         If !undef(type) && !undef(type_data): Pack desc(m,n) type_data, Unpack type
         If undef(type)  && !undef(type_data): Pack desc(m,n) type_data, Unpack type_data
         If !undef(type) && undef(type_data):  Pack desc(m,n) desc(m,n).type, Unpack type
         If undef(type)  && undef(type_data):  no action
      - Writing to matrix:   A -> desc(m, n) [type =.. type_data=…]
         If !undef(type) && !undef(type_data): Pack A type,   Unpack type_data on desc(m,n)
         If undef(type)  && !undef(type_data): Pack A A.type, Unpack type_data on desc(m,n)
         If !undef(type) && undef(type_data):  Pack A type,   Unpack desc(m,n).type on desc(m,n)
         If undef(type)  && undef(type_data):  Pack A A.type, Unpack desc(m,n).type on desc(m,n)
   * During propagation of dependencies between local tasks using
     keyword [type =...] on output and input dependencies.
      TASK_A: A -> B TASK_B
      TASK_B: B <- A TASK_A
          No type, no reshape
      ---
      TASK_A: A -> B TASK_B
      TASK_B: B <- A TASK_A [type = t2]
          Pack A.dtt, Unpack t2
      ---
      TASK_A: A -> B TASK_B [type = t1]
      TASK_B: B <- A TASK_A [type = t2]
          Pack t1, Unpack t2
      ---
      TASK_A: A -> B TASK_B [type = t1]
      TASK_B: B <- A TASK_A
          Pack t1, Unpack t1

  - NEW type specify by [type = ... ]