GoogleCodeExporter
commented
9 years ago Below are the proposed additions and modifications (against v1.2) to clarify
how multi-dimensional shared arrays and pointers-to-shared whose referenced
type is an array type work. Once I manage to get latex working correctly on
our development machines, I'll post the formal proposal.
[ADDED]
{3.*}
ultimate element
of a scalar is the scalar itself. For arrays, the ultimate element is the
ultimate element of an element of the array.
{3.*}
ultimate element type
for non-array types, the type itself. For array types, the ultimate element
type of an element of the array.
{3.*}
shared type
a type whose ultimate element type is shared-qualified.
{3.*}
local type
a type whose ultimate element type is not shared-qualified.
{6.4.2 *}
The affinity of a non-null pointer-to-shared whose reference type is a shared
array type is that of its first ultimate element, as a shared array type may
have ultimate elements on more than one thread.
{6.4.3 *}
If a non-null pointer-to-shared with definite blocksize is cast to a
pointer-to-local whose referenced type is not the ultimate element type of the
referenced type of the pointer-to-shared, the result is undefined.
{6.5.1.1 *}
EXAMPLE 4: shared array
shared TYPE array[THREADS]; /* NOTE: 'upc_affinityof( &array[i] )' could be something other than 'i' if TYPE is an array type */
[MODIFIED]
{3.2.3}
shared array
an array whose ultimate element type is shared-qualified.
{3.4}
pointer-to-shared
a pointer whose referenced type is a shared type.
{3.5}
pointer-to-local
a pointer whose referenced type is a local type.
{3.6.1}
shared access
an access using an expression whose type is a shared type.
{3.6.2}
local access
an access using an expression whose type is a local type.
{6.4.1.2 1}
The upc_localsizeof operator shall only apply to shared types or expressions
whose type is a shared type. All constraints on the sizeof operator [ISO/IEC00
Sec. 6.5.3.4] also apply to this operator.
{6.4.1.3 1}
The upc_blocksizeof operator shall only apply to shared types or expressions
whose type is a shared type. All constraints on the sizeof operator [ISO/IEC00
Sec. 6.5.3.4] also apply to this operator.
{6.4.1.4 1}
The upc_elemsizeof operator shall only apply to shared types or expressions
whose type is a shared type. All constraints on the sizeof operator [ISO/IEC00
Sec. 6.5.3.4] also apply to this operator.
{6.4.1.4 2}
The upc_elemsizeof operator returns the size, in bytes, of the ultimate element
type of a shared type or expression whose type is a shared type. The result of
upc_elemsizeof is an integer constant.
{6.4.2 2}
.... If the shared array has a definite block size, then the following example
describes pointer arithmetic:
shared [B] TYPE (*p), (*p1); /* B a positive integer, TYPE is a local type */
int i;
p1 = p + i;
{6.4.2 3}
...:
size_t elem_delta = i * (sizeof(TYPE) / upc_elemsizeof(TYPE))
upc_phaseof(p1) == (upc_phaseof(p) + elem_delta) mod B
upc_threadof(p1) == (upc_threadof(p) + (upc_phaseof(p) + elem_delta) div B) mod THREADS
{6.4.2 4}
...:
LT *p1, *p2;
shared ST (*s1), (*s2); /* LT is the non-shared-qualified version of the ultimate element type of ST */
p1 = (LT*) s1; /* Allowed if s1 has affinity to MYTHREAD */
p2 = (LT*) s2; /* Allowed if s2 has affinity to MYTHREAD */
{6.4.2 5}
...:
...
* The expression (((ptrdiff_t) upc_addrfield(s2)) - ((ptrdiff_t) upc_addrfield(s1))) shall evaluate to the same value as ((p2 - p1) * sizeof(LT)).
{6.5.1.1 10}
.... This factor is the nonnegative number of consecutive ultimate elements
(when evaluating pointer-to-shared arithmetic and array declarations) which
have affinity to the same thread....
{6.5.2 8}
...and no array object with automatic storage duration shall have an ultimate
element type that is shared-qualified.
{6.5.2.1 3}
Ultimate elements of shared arrays are distributed in a round-robin fashion, by
chunks of block-size ultimate elements, such that the i-th ultimate element has
affinity with thread (floor(i/block_size) mod THREADS).
{6.5.2.1 4}
In an array declaration, the type qualifier applies to the ultimate elements.
{6.5.2.1 9}
...:
...
shared [3] applies to the ultimate element type of T, which is int, regardless
of the typedef. ...
...
{7.2.3.5 4}
In the case of a statically allocated shared object with declaration:
shared [b] t d[s];
the totalsize argument shall be s * sizeof(t) and the nbytes argument shall be
b * upc_elemsizeof(t). ...Original comment by sdvor...@cray.com on 5 Feb 2013 at 5:58
Original issue reported on code.google.com by
johnson....@gmail.comon 13 Mar 2012 at 3:49