On Wed, 17 Jan 2001, Rick Jones wrote:
> certainly, i see by your examples how cork can make life easier on the
> developer - they can putc() the reply if they want. for a persistent
> http connection, there would be the cork and uncork each time, for a
> pipelined connection, it is basically a race - how does the client
> present requests to the connection, what are the speeds of that
> connection relative to the speed of the server getting replies into
> the socket that sort of thing.
such dynamic properties should IMO never become visible to user-space
interfaces i believe. TCP_CORK/MSG_MORE (which are both the same thing, in
a different interface) are a way to specify logical neighborhood of
app-side SENDs. I believe the most sensible and generic thing to do is to
require MSG_MORE information from the application: 'is it likely that the
application is going to SEND something soon, or not?'.
Submitting an exact timetable of planned future SENDs (with a fully
specified probability distribution of every expected future SEND event)
would be the most informative thing to do, but this is not very practical.
Basically MSG_MORE is a simplified probability distribution of the next
SEND, and it already covers all the other (iovec, nagle, TCP_CORK)
mechanizm available, in a surprisingly easy way IMO. I believe MSG_MORE is
very robust from a theoreticaly point of view.
To use this information to judge saturation situations properly is
completely up to the stack.
Ingo
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This archive was generated by hypermail 2b29 : Tue Jan 23 2001 - 21:00:17 EST