On Jan 2, 2007, at 5:11 PM, Sam Lang wrote:
Cool to hear that this MX is working with PVFS. I would like to
gather info about the assumptions we make (and that you had to
discover on your own) about the BMI API and semantics, so that we
can publish the process of adding BMI methods. I'll try to walk
through the emails that you've sent to the list as and send
something out, but if you have a list of other 'gotchas' that you
could send, that would be great to start with.
I can't think of any at the moment. It would be helpful to describe
the order of operations on the client versus the server (e.g.
BMI_meth_method_addr_lookup() with an id on the server and not on the
client, BMI_meth_method_addr_lookup() before initialize on the server
and after on the client, etc.).
While copying the large file, I see a lot of expected messages
arrive before the matching receive has been posted. I believe Sam
or RobL mentioned that if there are multiple messages per
operation, that the next receive is not posted until the previous
receive is completed. Is that correct? If so, would it be possible
to post all at once or would that break some of the other BMI
methods?
It wouldn't break BMI methods, and I think in most cases the
receives _should_ be posted around the same time as the sends. Can
you give more details about the sizes and endpoints? I'm guessing
that the side receiving expected messages before the receives are
posted is the server. Is that the case? Also, what sizes are the
messages?
Thanks,
-sam
One of the things we added to MX was an unexpected message callback
handler. This allows me to use an active message model for certain
messages (connection and unexpected). I ignore messages that should
be expected (based on their match bits). I have not printed detailed
info on the early expected messages, but I can print the tag and
length (I am only using a single client and single server). I will do
that Wednesday.
As for which side is seeing the early expected receives, it is the
one on the receiving side of the bulk transfer. Copying from client
to server, the server sees them and vice versa.
Scott
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