Strange, mine looks like this. The TX underrun counter is marked.
Maybe your terminal stops after 25 lines...?

Arie

S-44 SOC1 # cat /proc/net/emac_rfc2665_stats
ifSpeed                            : 100000000
dot3StatsDuplexStatus              : 3
ifAdminStatus                      : 1
ifOperStatus                       : 1
ifLastChange                       : 4294937879
ifInDiscards                       : 0
ifInErrors                         : 0
ifOutDiscards                      : 8043442
ifOutErrors                        : 0
ifInGoodFrames                     : 39789790
ifInBroadcasts                     : 32031783
ifInMulticasts                     : 537229
ifInPauseFrames                    : 0
ifInCRCErrors                      : 0
ifInAlignCodeErrors                : 0
ifInOversizedFrames                : 0
ifInJabberFrames                   : 0
ifInUndersizedFrames               : 0
ifInFragments                      : 0
ifInFilteredFrames                 : 1244044334
ifInQosFilteredFrames              : 0
ifInOctets                         : 2843366315
ifOutGoodFrames                    : 1300167711
ifOutBroadcasts                    : 2100224          your listing stops here.
ifOutMulticasts                    : 1098977666
ifOutPauseFrames                   : 0
ifDeferredTransmissions            : 0
ifCollisionFrames                  : 0
ifSingleCollisionFrames            : 0
ifMultipleCollisionFrames          : 0
ifExcessiveCollisionFrames         : 0
ifLateCollisions                   : 0
ifOutUnderrun                      : 0    <== increments if the burst priority 
is 255.
ifCarrierSenseErrors               : 0
ifOutOctets                        : 521111596
if64OctetFrames                    : 16130590
if65To127POctetFrames              : 40359478
if128To255OctetFrames              : 14660289
if256To511OctetFrames              : 36428177
if512To1023OctetFrames             : 79018404
if1024ToUpOctetFrames              : 1153360563
ifNetOctets                        : 1068573828
ifRxSofOverruns                    : 0
ifRxMofOverruns                    : 0
ifRxDMAOverruns                    : 0
S-44 SOC1 #

----------------------------------------------------------------------------
  ----- Original Message ----- 
  From: Bin Liu 
  To: Arie de Muijnck ; [email protected] 
  Sent: Tuesday, March 10, 2009 19-55
  Subject: Re: reading compat flash causing emac network drop packets?


  Below is the output from the cat, 
  /proc/net# cat ./emac_rfc2665_stats
  ifSpeed                            : 100000000
  dot3StatsDuplexStatus              : 3
      ...
  ifInQosFilteredFrames              : 0
  ifInOctets                         : 1103907312
  ifOutGoodFrames                    : 10122834
  ifOutBroadcasts                    : 7

  I can't find the TX underrun count, also from other emac_ files.
  Yes, I am streaming using UDP.

  Thanks,
  Bin



  On Mon, Mar 9, 2009 at 3:30 PM, Arie de Muijnck <[email protected]> wrote:

    NFS is using a TCP connection which retries after errors. I suppose you use 
UDP to stream video data, and then you see the errors.
    If you do a "cat /proc/net/emac_rfc_*" you get a list of statistics 
counters. Look for the TX underrun count, it should stay zero. If not then the 
DMA burst size is the problem.

    Regards,
    Arie de Muijnck.

      ----- Original Message ----- 
      From: Bin Liu 
      To: Arie de Muijnck 
      Sent: Monday, March 09, 2009 16-11
      Subject: Re: reading compat flash causing emac network drop packets?


      Thank you for the reply, I will try that out and let you know the outcome.
      One question in my mind is if that is the case, why nfs reading can still 
go through.

      Bin


      On Fri, Mar 6, 2009 at 2:55 AM, Arie de Muijnck <[email protected]> wrote:

          From: Bin Liu 


          Hi, I am trying to read transport stream file from compat flash and 
stream out to the ethernet port,
          and I am using customer DM6446 board, running 2.6.10 Linux.
          When bitrate is low, less than 10 Mbps, there is no problem, but if 
bitrate goes up to anything higher
          than 15 Mbps, I am seeing the packet drops.
          So far I have made sure there is no packet drop before packet is 
handed over to ethernet emac driver,
          and the cpu usage is not very high(around 30%) when dropping packet, 
if I read the file from nfs server seem to be fine, so I doubt the cf driver is 
causing the packet drop, anybody can shad some light 
        This is I think a known 'feature'. 

        The maximum length of a DDRAM access burst is default set to 
'infinite', meaning a low-priority access may block a high-priority DMA 
transfer such as used for the EMAC TX. See the errata sheet for the fix, the 
memory burst control register is mentioned there, the default is the special 
value 0xFF meaning infinite and should be set to 0x20 meaning 32.

        Regards,
        Arie de Muijnck



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