Gianfar is slower than fcc_enet on MPC8541 ???

[Laurent Lagrange]

Hi Pantelis,

Thanks for the express reply.

I know that what I say seems incredible. But I don't understand what NAPI
does.
My measure is very simple. I display a message on the client when 1000
exchanges are done.
I already check the ifconfig stats on the board after some seconds.
The measures seems the same with or without NAPI.

More details ?
Thanks again
Laurent


  -----Message d'origine-----
  De : Pantelis Antoniou [mailto:pantelis.antoniou at gmail.com]
  Envoyé : mar. 14 février 2006 16:29
  À : Laurent Lagrange
  Cc : linuxppc-embedded at ozlabs.org
  Objet : Re: Gianfar is slower than fcc_enet on MPC8541 ???


  Hi Laurent,

  I found that pretty hard to believe.

  What are you measuring exactly?

  Speed of replies? If so it's explainable since the TSECs use
  NAPI.

  Regards

  Pantelis


  On 2/14/06, Laurent Lagrange <lagrange at fr.oleane.com> wrote:

    Hello,

    I work on a cutom MPC8541 board with Linux 2.6.9.
    The kernel activates the L1 cache (instructions and data)
    and the L2 cache (entirely used as cache and not as sram).

    I configure
    1 FCC (FCC1),
    2 TSECs with or without NAPI (no effect) but without stashing in L2
sram.
    All PHYs are automatically configured in 100MB full duplex.

            eth0: Gianfar Ethernet Controller Version 1.1, 00:10:cd:48:48:e0
            eth0: Running with NAPI disabled
            eth0: 64/64 RX/TX BD ring size
            eth1: Gianfar Ethernet Controller Version 1.1, 00:10:cd:48:48:e1
            eth1: Running with NAPI disabled
            eth1: 64/64 RX/TX BD ring size
            eth2: FCC ENET Version custom, 00:10:cd:48:48:e2

    Then I launch 3 simple TCP servers, one on each ports.

    From remote machines I runs 3 TCP clients.
    The client sends messages of 1000 bytes,
    The server receives and echoes the message
    The client receives the echoed message, check the content
    and sends a new message again.

    The result is that the 2 TSECs are 2 times slower than the FCC.

    If I run a "top" application on the board, I use less than 10% of the
CPU
    Each port consumes about 1/3 of the CPU.

    Any idea on how to configure the gianfar driver ?

    Thanks
    Laurent


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