[openbeosnetteam] Re: Dial-Up

----- Original Message ----- 
From: "Bruno G. Albuquerque" <bga@xxxxxxxxxxxxx>


> On Wed, 9 Apr 2003, Axel =?iso-8859-1?q?D=F6rfler ?= wrote:
>
> > It can't achieve this alone. The networking drivers would have to
be
> > changed for this - the read/write functions of the driver mustn't
be
> > used when want to remove all copies (since we can't remove the one
that
> > happens when the recv() function is called).
> > We could also provide a zero copying userland C++ API - that would
be a
> > nice advantage over using the standard BSD socket API.
>
> Just to remind that it is ok to have zero-copy for receiving data,
but
> zero-copy for *SENDING* data (specially TCP packets) is overkill and
will
> actually decrease performance (due to retransmission).
>

If I understand well: if you intend to do zero_copy for TCP
transmission you should keep a sent segment in memory until the OS
receive an TCP ack for that one.
Is it the management of this which is causing the overkill or is it
more a memory usage impact ?

If not, where the performance issue is coming from ? (it is not very
clear for me :-)

     Regards,

          Emmanuel

Other related posts: