[ixp1200] Receiving Data from a particular port on IXP2400

[David Mentre]

Hello Sanjay,

> From: Sanjay Kumar [mailto:ksanjay at cc.gatech.edu]
> Sent: Friday, February 27, 2004 11:27 PM

> I am writing a microengine rx/tx driver for ixp2400. for the 
> receive side, 
> i want to allocate a particular thread for particular MAC 
> port. 

> All I could find out was that MSF's receive status word (RSW) 
> contains a 
> field which tells which physical port this mpacket came from (e.g. in 
> POS-PHY Level 3, 32 bit MPHY mode, the 5 LSB bits of RSW0 
> will tell this 
> information). and then it is the thread's job to read this 
> field and sort 
> out different mpackets received from different ports. This 
> will make the 
> driver pretty messy especially if you are employing multiple 
> threads to 
> receive mpackets from a particular port.

>From my own reading of Intel docs, you can't wait on a given logical port,
only for a physical port, for example in SPHY-4 mode.

Why not reuse Intel design, i.e. one full micro-engine (8 threads) that
receives from all ports? You could modify this block to output assembled
network packets to different scratch ring if you want to have port
differentiation.

In my opinion (but I may be wrong), Intel engineers have optimized receive
block for performance and it would be hard to do a better job.

Sincerely yours,
david
-- 
David Mentré <mentre at tcl.ite.mee.com> - Research engineer (Ph.D.)
Mitsubishi Electric ITE-TCL / European Telecommunication Research Lab
Phone: +33 2 23 45 58 29 / Fax: +33 2 23 45 58 59 
http://www.mitsubishi-electric-itce.fr