IPC transfer message question.

[Suresh Iyer]

I am working on some modifying IPC behaviour for an alternative
scheduling mechanism based on temporal partioning.
I had a question related to L4 embedded IPC transfer message part ( I
dont know whether this could be an L4 generic question ).

 In the  IPC implementation for l4 embedded , i see that the data is
transferred only( ie transfer_messsge called ) only during a send
phase of the code. Does this have to be the case ?

In other words, lets assume A is sending to B and B is not ready to
receive.. If we switch to B , and
the code reaches Bs receive phase, cant B transfer the data from As
utcb to Bs utcb by calling transfer_message of L4ka ? or do we have to
switch back to A to make the transfer message happen ?
The L4 embedded code seems to be doing this . Any reasons for this ?

would really appreciate a prompt answer, Thanks so much !!
suresh.