On Oct 18, 2006, at 4:11 PM, Troy Benjegerdes wrote:
One question is what does PVFS_Request_contiguous actually do?
It creates a request structure that essentially contains the size
and offset into the memory buffer.
Since I am using the same buffer all the time would it be ok to
setup the request once and then reuse it so long as the io size
is the same?
Yes. The request structure doesn't get modified by the IO call.
You (correctly) use PVFS_BYTE for the file request. The reason
you can't just use PVFS_BYTE for the memory request is that the
size has to be encapsulated in the request as well (while the file
request gets tiled based on the actual file size).
-sam
Okay, so, is PVFS_Request_contiguous just a fancy way to allocate
memory?
In that case, can we just use PVFS_Request_contiguous (or add a
function like it) to allocate our application data buffer that we
will be reading/writing all the data from? Then we can bypass all
the memory registration crap and just register the buffer once.
No it doesn't do any allocation, just encapsulation of the offset and
size parameters.
-sam
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