The MRDSL parameter has no effect on iSER, as the RFC describes.
How to transfer data to satisfy a command is solely up to the
target. So you would need both big requests from the client, then
look at how the target will send the data.
I've only used 512 kB for the RDMA transfer size from the target, as
it matches the default client size and was enough to get good
performance out of my IB gear and minimizes resource consumption on
the target. It's currently hard-coded as a #define. There is no
provision in the protocol for the client to dictate the value.
If others want to spend some effort trying to tune stgt for iSER,
there are a fair number of comments in the code, including a big one
that explains this RDMA transfer size issue. And I'll answer
informed questions as I can. But I'm not particularly interested in
arguing about which implementation is best, or trying to interpret
bandwidth comparison numbers from poorly designed tests. It takes
work to understand these issues.
-- Pete
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