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Re: gigabit ethernet

To: satya srikanth <satyasrikanth2001@xxxxxxxxx>
Subject: Re: gigabit ethernet
From: "Xiaoliang (David) Wei" <weixl@xxxxxxxxxxx>
Date: Thu, 12 Feb 2004 01:34:32 -0800
Cc: netdev@xxxxxxxxxxx
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Hi Satya,

Did you check the CPU utilization? If you use smaller packet size, the interrupt rate may be a problem. You can modulate the NIC's interrupt rate. See the document for details:
http://www.intel.com/support/network/adapter/1000/e1000.htm#parameters


Also, I assume the round trip propagation delay for your connections is very small (such as <10ms)?


-David

satya srikanth wrote:
Sir,
    I need some help from you. I am using 2 xeon(2
GHz) machines each with two processors running linux
2.4.20-8smp kernel and having intel PRO/1000 gigabit
adapter NIC card(e1000 driver). I tried connecting
both of them using a gigabit switch. I am getting
gigabit speed only if I use my own TCP sockets sending
packets of size around 1400 bytes. If I send packets
of size around 500 bytes, I am getting maximum of only
500 Mbps. I noticed that NIC is receiving all the
packets but they are getting dropped in the kernel.
        I tried changing the settings like
netdev_max_backlog to 30000 and rmem_max, wmem_max and
txqueuelen, but of no use. Can you please suggest some
changes that I need to make to achieve this speed.
(Like changing number of Rx interrupts, Tx interrupts
etc). Can you please suggest some other links where I
can get some useful information. Will linux router
project LRP help me to achieve it.

        with regards,
        Satya Srikanth.



--
------------------------------------------------------
Xiaoliang (David) Wei   Graduate Student of CS@Caltech
WWW: http://www.cs.caltech.edu/~weixl
======================================================



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