Hello Andrew, Thanks for this explanation. It was very helpfull to me to understand the function of BTL, specially about the correct sequence of the function path.
I was wondering if this mail, can be included in a commentary inside btl.h or an README file at the BTL base directory to help other people too. For now, I don't have more questions, :) Thanks Leslie 2006/1/19, Andrew Friedley <afrie...@open-mpi.org>: > Hello, > > Apologies for the late response. I've been learning the BTL interface > myself recently, and was asked to come up with answers for you. > Hopefully my response is useful, let me know if you have more questions. > > Andrew > > > Leslie Watter wrote: > > What I need? To know how and what functions is necessary to perform a > > minimalist > > implementation of a new btl, registering it and make it usable. > > First, two component functions are required - mca_component_open and > mca_component_close. > > Two structs need to be set up - one for the component, and one for each > module. The component struct is called mca_btl_<btl>_component_t, and > extends mca_btl_base_component_t. The module struct is called > mca_btl_<btl>_module_t, and extends mca_btl_base_module_t. > > Only one instance of the component struct is created, while many module > structs may be created (usually one per network interface). > > Inside these structs are several function pointers that must be filled > in. For the component, the btl_init and btl_progress fields are > required. For each module, the following functions are required: > > btl_add_procs > btl_del_procs > btl_register > btl_finalize > btl_alloc > btl_free > btl_prepare_src > btl_send > > The remaining three - btl_prepare_dst, btl_put, and btl_get - are > optional RDMA functions. Their presence is indicated by the btl_flags > field in the module struct. If either MCA_BTL_FLAGS_PUT or > MCA_BTL_FLAGS_GET are set, the respective put/get function must be set > in the struct, as well as prepare_dst. > > See btl.h and tcp/btl_tcp.h for examples. > > > > 1) Inicialization > > > > component open > > component init > > component create instances > > btl tcp create > > component create_listen > > btl tcp setsocket options > > component exchange > > > > btl tcp add procs > > endpoint construct ( executed * number of endpoints ) > > btl tcp del procs > > btl tcp register > > del procs should not be getting called here. Otherwise this looks correct. > > <big cut> > > > This is the sequence I have found executing the TCP BTL code. Please fell > > free > > to correct the place of sections. > > Other than the del procs call, this looks correct. Tim Woodall had some > additional comments about typical send cases: > > From the perspective of the PML<->BTL interface, the PML will in > general call: > > 1) btl_alloc followed by btl_send for short control messages > 2) btl_prepare_src followed by btl_send for send/recv semantics > 3) btl_prepare_dst/btl_prepare_src/btl_put for rdma semantics > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > -- Leslie H. Watter
