Gather-scatter communication using OpenSHMEM one-sided puts with per-rank signaling for completion (OpenSHMEM 1.5). More...

Inheritance diagram for gs_shmem::gs_shmem_t:

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Collaboration diagram for gs_shmem::gs_shmem_t:

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Public Member Functions
procedure, pass(this)	init (this, send_pe, recv_pe)
	Initialise OpenSHMEM based communication method.

procedure, pass(this)	free (this)
	Deallocate OpenSHMEM based communication method.

procedure, pass(this)	nbsend (this, u, n, tag, deps, strm)
	Pack the gathered shared dofs into the symmetric send buffer and issue non-blocking puts with signaling to each neighbor's recv buffer. Before each put, wait for the receiver's ack of our previous round so we never overwrite a buffer the receiver hasn't consumed yet.

procedure, pass(this)	nbrecv (this, tag)
	No-op: receives are completed via remote put-with-signal.

procedure, pass(this)	nbwait (this, u, n, op, strm)
	Wait per-neighbor for the signal indicating that data has landed, apply the gather-scatter operation from the recv buffer into u, and ack the sender so they may overwrite the buffer in the next round.

procedure, pass(this)	nbsend_vec (this, u, n, nc, tag, deps, strm)
	Fused nc-component send: pack nc contiguous component blocks per peer slab and put nc*ndofs reals with a single signal. Buffer indexing and put size scale by nc; the per-rank signalling is unchanged.

procedure, pass(this)	nbrecv_vec (this, tag, nc)
	No-op: receives are completed via remote put-with-signal.

procedure, pass(this)	nbwait_vec (this, u, n, nc, op, strm)
	Fused nc-component wait/reduce: per peer, wait on the data signal and reduce nc component blocks into u, then ack the sender.

procedure(gs_comm_init), deferred, pass	init gs_comm_init

procedure(gs_comm_free), deferred, pass	free gs_comm_free

procedure(gs_nbsend), deferred, pass	nbsend gs_nbsend

procedure(gs_nbrecv), deferred, pass	nbrecv gs_nbrecv

procedure(gs_nbwait), deferred, pass	nbwait gs_nbwait

procedure, pass(this)	init_dofs (this)

procedure, pass(this)	free_dofs (this)

procedure, pass(this)	init_order (this, send_pe, recv_pe)
	Obtains which ranks to send and receive data from.

procedure, pass(this)	free_order (this)

procedure, pass(this)	nbsend_vec (this, u, n, nc, tag, deps, strm)
	Fused vector halo exchange. Default implementations abort; backends that set vec_supported = .true. override them.

procedure, pass(this)	nbrecv_vec (this, tag, nc)
	Default fused vector receive. Abort unless a backend overrides it.

procedure, pass(this)	nbwait_vec (this, u, n, nc, op, strm)
	Default fused vector wait/reduce. Abort unless a backend overrides it.

Public Attributes
type(gs_shmem_buf_t)	send_buf

type(gs_shmem_buf_t)	recv_buf

type(c_ptr)	data_signals_ptr = C_NULL_PTR

type(c_ptr)	ack_signals_ptr = C_NULL_PTR

integer(kind=i8)	iter = 0

type(stack_i4_t), dimension(:), allocatable	send_dof
	A list of stacks of dof indices local to this process to send to rank_i.

type(stack_i4_t), dimension(:), allocatable	recv_dof
	recv_dof(rank_i) is a stack of dof indices local to this process to receive from rank_i. size(recv_dof) == pe_size

integer, dimension(:), allocatable	send_pe
	Array of ranks that this process should send to.

integer, dimension(:), allocatable	recv_pe
	array of ranks that this process will receive messages from

logical	vec_supported = .false.
	Whether this backend implements the fused vector (multi-component) halo exchange (nbsend_vec/nbrecv_vec/nbwait_vec). When .false., the gs_op_r3 caller falls back to nc independent scalar exchanges.

Detailed Description

Each PE allocates symmetric send and recv buffers sized to the global maximum number of dofs (so puts can target a well-defined offset on the remote PE's recv buffer) plus two symmetric uint64 arrays of size pe_size, indexed by the remote PE's rank: data_signals[r] holds an "iter" value written by PE r when it has put data into our recv buffer (via shmem_putmem_signal_nbi); ack_signals[r] holds an "iter" value written by PE r after it has consumed our most recent put (via shmem_uint64_atomic_set). The sender waits on its own ack_signals[dst] before each put so a fast sender cannot overwrite a buffer the receiver hasn't consumed.

Per-rank slot indexing avoids the slot-exchange handshake that a neighbor-list-position scheme would require, which is fragile because send_pe and recv_pe are pushed independently in gs_schedule and may differ in size and ordering.

Definition at line 91 of file gs_shmem.F90.

Member Function/Subroutine Documentation

◆ free() [1/2]

procedure, pass(this) gs_shmem::gs_shmem_t::free ( class(gs_shmem_t), intent(inout) this )

Definition at line 109 of file gs_shmem.F90.

◆ free() [2/2]

procedure(gs_comm_free), deferred, pass gs_comm::gs_comm_t::free

pure virtualinherited

Definition at line 70 of file gs_comm.f90.

◆ free_dofs()

procedure, pass(this) gs_comm::gs_comm_t::free_dofs ( class(gs_comm_t), intent(inout) this )

inherited

Definition at line 75 of file gs_comm.f90.

◆ free_order()

procedure, pass(this) gs_comm::gs_comm_t::free_order ( class(gs_comm_t), intent(inout) this )

inherited

Definition at line 77 of file gs_comm.f90.

◆ init() [1/2]

procedure, pass(this) gs_shmem::gs_shmem_t::init	(	class(gs_shmem_t), intent(inout)	this,
		type(stack_i4_t), intent(inout)	send_pe,
		type(stack_i4_t), intent(inout)	recv_pe
	)

Definition at line 108 of file gs_shmem.F90.

◆ init() [2/2]

procedure(gs_comm_init), deferred, pass gs_comm::gs_comm_t::init

pure virtualinherited

Definition at line 69 of file gs_comm.f90.

◆ init_dofs()

procedure, pass(this) gs_comm::gs_comm_t::init_dofs ( class(gs_comm_t), intent(inout) this )

inherited

Definition at line 74 of file gs_comm.f90.

◆ init_order()

procedure, pass(this) gs_comm::gs_comm_t::init_order	(	class(gs_comm_t), intent(inout)	this,
		type(stack_i4_t), intent(inout)	send_pe,
		type(stack_i4_t), intent(inout)	recv_pe
	)

inherited

Parameters

send_pe,only	contains rank ids this porcesss should send to
recv_pe,only	the ranks this process should receive from

Definition at line 76 of file gs_comm.f90.

◆ nbrecv() [1/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbrecv	(	class(gs_shmem_t), intent(inout)	this,
		integer, intent(in)	tag
	)

Definition at line 111 of file gs_shmem.F90.

◆ nbrecv() [2/2]

procedure(gs_nbrecv), deferred, pass gs_comm::gs_comm_t::nbrecv

pure virtualinherited

Definition at line 72 of file gs_comm.f90.

◆ nbrecv_vec() [1/2]

procedure, pass(this) gs_comm::gs_comm_t::nbrecv_vec	(	class(gs_comm_t), intent(inout)	this,
		integer, intent(in)	tag,
		integer, intent(in)	nc
	)

inherited

Definition at line 81 of file gs_comm.f90.

◆ nbrecv_vec() [2/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbrecv_vec	(	class(gs_shmem_t), intent(inout)	this,
		integer, intent(in)	tag,
		integer, intent(in)	nc
	)

Definition at line 114 of file gs_shmem.F90.

◆ nbsend() [1/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbsend	(	class(gs_shmem_t), intent(inout)	this,
		real(kind=rp), dimension(n), intent(inout)	u,
		integer, intent(in)	n,
		integer, intent(in)	tag,
		type(c_ptr), intent(inout)	deps,
		type(c_ptr), intent(inout)	strm
	)

Definition at line 110 of file gs_shmem.F90.

◆ nbsend() [2/2]

procedure(gs_nbsend), deferred, pass gs_comm::gs_comm_t::nbsend

pure virtualinherited

Definition at line 71 of file gs_comm.f90.

◆ nbsend_vec() [1/2]

procedure, pass(this) gs_comm::gs_comm_t::nbsend_vec	(	class(gs_comm_t), intent(inout)	this,
		real(kind=rp), dimension(nc*n), intent(inout)	u,
		integer, intent(in)	n,
		integer, intent(in)	nc,
		integer, intent(in)	tag,
		type(c_ptr), intent(inout)	deps,
		type(c_ptr), intent(inout)	strm
	)

inherited

Parameters

u	compact shared buffer, component-outer: u((c-1)*n + idx)
n	number of shared dofs (per component)
nc	number of components

Definition at line 80 of file gs_comm.f90.

◆ nbsend_vec() [2/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbsend_vec	(	class(gs_shmem_t), intent(inout)	this,
		real(kind=rp), dimension(nc*n), intent(inout)	u,
		integer, intent(in)	n,
		integer, intent(in)	nc,
		integer, intent(in)	tag,
		type(c_ptr), intent(inout)	deps,
		type(c_ptr), intent(inout)	strm
	)

Parameters

u	compact shared buffer, component-outer: u((c-1)*n + idx).

Definition at line 113 of file gs_shmem.F90.

◆ nbwait() [1/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbwait	(	class(gs_shmem_t), intent(inout)	this,
		real(kind=rp), dimension(n), intent(inout)	u,
		integer, intent(in)	n,
		integer	op,
		type(c_ptr), intent(inout)	strm
	)

Definition at line 112 of file gs_shmem.F90.

◆ nbwait() [2/2]

procedure(gs_nbwait), deferred, pass gs_comm::gs_comm_t::nbwait

pure virtualinherited

Definition at line 73 of file gs_comm.f90.

◆ nbwait_vec() [1/2]

procedure, pass(this) gs_comm::gs_comm_t::nbwait_vec	(	class(gs_comm_t), intent(inout)	this,
		real(kind=rp), dimension(nc*n), intent(inout)	u,
		integer, intent(in)	n,
		integer, intent(in)	nc,
		integer	op,
		type(c_ptr), intent(inout)	strm
	)

inherited

Definition at line 82 of file gs_comm.f90.

◆ nbwait_vec() [2/2]

procedure, pass(this) gs_shmem::gs_shmem_t::nbwait_vec	(	class(gs_shmem_t), intent(inout)	this,
		real(kind=rp), dimension(nc*n), intent(inout)	u,
		integer, intent(in)	n,
		integer, intent(in)	nc,
		integer	op,
		type(c_ptr), intent(inout)	strm
	)

Definition at line 115 of file gs_shmem.F90.

Member Data Documentation

◆ ack_signals_ptr

type(c_ptr) gs_shmem::gs_shmem_t::ack_signals_ptr = C_NULL_PTR

Definition at line 101 of file gs_shmem.F90.

◆ data_signals_ptr

type(c_ptr) gs_shmem::gs_shmem_t::data_signals_ptr = C_NULL_PTR

Definition at line 97 of file gs_shmem.F90.

◆ iter

integer(kind=i8) gs_shmem::gs_shmem_t::iter = 0

Definition at line 106 of file gs_shmem.F90.

◆ recv_buf

type(gs_shmem_buf_t) gs_shmem::gs_shmem_t::recv_buf

Definition at line 93 of file gs_shmem.F90.

◆ recv_dof

type(stack_i4_t), dimension(:), allocatable gs_comm::gs_comm_t::recv_dof

inherited

Definition at line 57 of file gs_comm.f90.

◆ recv_pe

integer, dimension(:), allocatable gs_comm::gs_comm_t::recv_pe

inherited

Definition at line 63 of file gs_comm.f90.

◆ send_buf

type(gs_shmem_buf_t) gs_shmem::gs_shmem_t::send_buf

Definition at line 92 of file gs_shmem.F90.

◆ send_dof

type(stack_i4_t), dimension(:), allocatable gs_comm::gs_comm_t::send_dof

inherited

Definition at line 54 of file gs_comm.f90.

◆ send_pe

integer, dimension(:), allocatable gs_comm::gs_comm_t::send_pe

inherited

Note: : this will usually be fewer than the total number of ranks size(send_pe) <= pe_size

Definition at line 61 of file gs_comm.f90.

◆ vec_supported

logical gs_comm::gs_comm_t::vec_supported = .false.

inherited

Definition at line 67 of file gs_comm.f90.

The documentation for this type was generated from the following file:

/home/runner/work/neko/neko/src/gs/gs_shmem.F90

Public Member Functions

Public Attributes

Detailed Description

Member Function/Subroutine Documentation

◆ free() [1/2]

◆ free() [2/2]

◆ free_dofs()

◆ free_order()

◆ init() [1/2]

◆ init() [2/2]

◆ init_dofs()

◆ init_order()

◆ nbrecv() [1/2]

◆ nbrecv() [2/2]

◆ nbrecv_vec() [1/2]

◆ nbrecv_vec() [2/2]

◆ nbsend() [1/2]

◆ nbsend() [2/2]

◆ nbsend_vec() [1/2]

◆ nbsend_vec() [2/2]

◆ nbwait() [1/2]

◆ nbwait() [2/2]

◆ nbwait_vec() [1/2]

◆ nbwait_vec() [2/2]

Member Data Documentation

◆ ack_signals_ptr

◆ data_signals_ptr

◆ iter

◆ recv_buf

◆ recv_dof

◆ recv_pe

◆ send_buf

◆ send_dof

◆ send_pe

◆ vec_supported