[openib-general] Handling SM class (SMInfo vs. other queries)
Michael S. Tsirkin
mst at mellanox.co.il
Sat Oct 23 14:02:56 PDT 2004
Hello!
Quoting r. Roland Dreier (roland at topspin.com) "Re: [openib-general] Handling SM class (SMInfo vs. other queries)":
> Fab> This seems to imply that received MAD completion processing
> Fab> will never happen in the context of the CQ notification
> Fab> callback, and always require a context switch to a thread
> Fab> context that can block while the MADs are handed off. Am I
> Fab> following correctly? Do we want to have such a context
> Fab> switch for every received MAD?
>
> This design decision (to handle MAD completions in thread context) was
> made a while ago. However I agree that long term it would make sense
> to move at least the SMA processing back to interrupt/tasklet context
> (and switch the local MAD interface to be asynch, of course).
>
> - R.
I think the difficulty with the last one is that (at least for Tavor)
process local mad can block, since there is a limited
number of outstanding commands. Of course you could always
make it non-blocking by dropping the MAD if the command interface
is busy ... no idea if this will improve or decease performance, though.
MST
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