[rds-devel] OK - so what is a common completion model / unified poll in RDS anyway ?

Richard Frank richard.frank at oracle.com
Thu Nov 15 04:19:10 PST 2007

A lot of what's driving the choice of flags is driven by the desire to 
use common code in our application for all socket implementations - 
including UDP and RDS.  This is where the pollout / pollin originates - 
it's transparent - well 99.9% - to the app that it is running on RDS.

If we want to change the flags - we can not do it in RDS v3 - due to our 
requirement of not wanting to break RDS v2 applications.

Olaf Kirch wrote:
> On Thursday 15 November 2007 03:45, Richard Frank wrote:
>> Poll for RDS sockets it cabable of detecting all of the following events 
>> and waking a waiter:
>> a) incoming messages (pollin)
>> b) send space available (pollout)
>> c) any rdma completion or a specific rdma completion (pollin)
>> d) congestion removed from a destination (pollin)
> Please, let's not overload POLLIN even more. For RDMA completions
> we could at least use POLLMSG (yes, it's Linux-specific).
> For congestion updates, I think we still need a better solution
> than POLLIN. What about POLLRDBAND? It's not such a great fit either,
> because there's nothing to be read from the socket - but at
> least it's distinct from other values.
> Olaf

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