What Dev board/FPGA are you using?
If it is Spartan 3A DSP 1800 (possibly other
similar models are affected also) there is a problem with the physical layer
DCM phase shift in the gmii – currently under investigation by Xilinx (I’ve
only experimented at gigabit speeds though).
You could try adding the following line to
the implementation\system.ucf – in the GMII Receiver side DCM constraints
*gmii_rxc_dcm PHASE_SHIFT = 76”
This has yielded significant performance
increases in performance at gigabit for me – but I still get some dropped
frames of data.
With various tests (again at gigabit) I have
found that generally the bigger the ICache and DCache the better, mainly ICache,
(32K for both allows ~4.7MBytes/sec. ).
The most significant increase I have seen
is by increasing the MTU to 8982 (~19.6 MBytes/sec) but this involves
increasing your TEMAC fifos to 16K to handle the larger frames, and also means
your infrastructure must support Jumbo frames.
Hope this helps. I would probably
try the larger ICache & DCache first!
If you do find any more performance let me
know – always nice to have a bit more bandwidth headroom!
On Behalf Of Terry ONeal
Sent: 03 November 2008 22:21
Ethernet performance with xps_ll_temac
Hi All, I'm working on a
Microblaze system (MMU enabled) that uses xps_ll_temac, and I'm seeing poor
network performance when running netperf. The phy is in 100Mb mode and
I'm seeing around 2.5Mb/s with the netperf TCP_STREAM test. Microblaze caches
are 16K, temac buffers are 4k, barrell shifter and HW multiplier are turned on.
I'm using petalinux sources I pulled from the svn repository on 10/16/08.
What is interesting is that it appears that the kernel is losing timer ticks -
if I configure netperf to run the test for 10 seconds, it actually takes 20
seconds (per my watch) to run, but the kernel only thinks it's been runnning
for 10 seconds. So it appears the the ll_temac driver is hogging the CPU.
I also put togther my own application that simply creates a UDP socket and
sends data through it as fast as it can - the performance is a bit better than
the netperf TCP test but still way off from what I'm expecting (at least
Has anyone had better luck with xps_ll_temac performance? Any suggestions as to
what may be going that is limiting the performance?
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