[U-Boot-Users] MPC8xx-board: just 10MBit transfer rate

[U-Boot-Users] MPC8xx-board: just 10MBit transfer rate

[Josef Angermeier]

Dear u-boot users,

i got u-boot 1.1.3 and linux 2.4.25 running on my custom MPC875-board.
But the ethernet-connection (FEC-Controller) seems to be abit slow. The
MII-transceiver chip autonegotiates a speed of 100MBit but when
downloading files via tftp/ftp in u-boot or linux the transfer seems to
happen in 10MBit mode.

Could this be caused by the low system clock (40MHz) ? What else ?

Best regards,
Josef

[U-Boot-Users] MPC8xx-board: just 10MBit transfer rate

[Pantelis Antoniou]

On Tuesday 14 March 2006 17:37, Josef Angermeier wrote:
> 
> Dear u-boot users,
> 
> i got u-boot 1.1.3 and linux 2.4.25 running on my custom MPC875-board.
> But the ethernet-connection (FEC-Controller) seems to be abit slow. The
> MII-transceiver chip autonegotiates a speed of 100MBit but when
> downloading files via tftp/ftp in u-boot or linux the transfer seems to
> happen in 10MBit mode.
> 
> Could this be caused by the low system clock (40MHz) ? What else ?
> 
> Best regards,
> Josef
> 
> 

TFTP is not a speed demon. This is a protocol issue.
Has nothing to do with the ethernet negotiated rate.

Pantelis

[U-Boot-Users] MPC8xx-board: just 10MBit transfer rate

[Jerry Van Baren]

Josef Angermeier wrote:
> Dear u-boot users,
> 
> i got u-boot 1.1.3 and linux 2.4.25 running on my custom MPC875-board.
> But the ethernet-connection (FEC-Controller) seems to be abit slow. The
> MII-transceiver chip autonegotiates a speed of 100MBit but when
> downloading files via tftp/ftp in u-boot or linux the transfer seems to
> happen in 10MBit mode.
> 
> Could this be caused by the low system clock (40MHz) ? What else ?
> 
> Best regards,
> Josef

Crank up ethereal and see what packets are being transmitted, received, 
and the time between packets.  I suspect you will see either gross 
delays or retransmissions (and quite possibly both), indicating packet 
handling problems of some form or another. (Unreasonable to speculate 
what, without seeing the ethereal dump.  Once you see the packet 
pattern, the problem usually is fairly obvious.)

If not, you need to recalibrate your expectations. :-)  TFTP is a 
transmit-acknowledgment protocol with no pipelining, so packet n+1 
doesn't get transmitted until packet n is acknowledged.  If the <ack> is 
slow, your transfer rate will be slow also.

gvb