[realtek] Question: Rx Ring Buffers in the rtl8139 module

joerg.beyer@email.de joerg.beyer@email.de
Thu Aug 29 04:26:01 2002


I have a question, regarding the Rx Ring Buffer architecture of the
rtl8139 module. let me quote from the source documentation:

--- begin quote ---
IIIa. Rx Ring buffers

The receive unit uses a single linear ring buffer rather than the more
common (and more efficient) descriptor-based architecture.  Incoming frames
are sequentially stored into the Rx region, and the host copies them into

Comment: While it is theoretically possible to process many frames in place,
any delay in Rx processing would block the Rx ring and cause us to drop
frames.  It would be difficult to design a protocol stack where the data
buffer could be recalled by the device driver.

--- end quote ---

I understand that all received packets are put in a ring buffer, while more efficient
NIC drivers build a descriptor based buffer architeture. Is it possilble, or has anybody
tried, to use a descriptor based buffer layout with the 8139 card?

Which is the most simple example of a descriptor based Rx Buffer NIC module?