Valdis.Kletnieks@vt.edu wrote:
>On Tue, 22 Jul 2003 00:42:45 CDT, Matthew Hunter <matthew@infodancer.org> said:
>
>
>
>>Running more tests, it turns out the speed problem is isolated to
>>the one machine, and only to *receiving* data. Sending goes at
>>8 M/s to other machines from the client machine. Sending from
>>any machine to the client machine is slowed down, not just from
>>the server.
>>
>>
>
>These symptoms sound suspiciously like a 100BaseT auto-negotiation
>problem. With some combinations of gear, if one end is set to auto-negotiate
>and the other end is nailed to full/half duplex (sorry, can't remember which and
>I've not my caffiene yet), things go horribly wrong and many packets
>dissapear silently on transmission, forcing retransmit timeouts and bad
>throughput. Basically, you end up with one end thinking it's full duplex,
>the other end at half - and if the full duplex side ever sends a packet while
>the half side is sending, the packet's lost.
>
>Try nailing the devices on both ends of the cat-5 to the same thing (full or
>half). This can of course be interesting if you have an unmanaged hub that
>doesn't give you a choice...
>
>
>
>
>
You should be able to use mii-tool, or ethtool (one or both should
work) to check the state your ethernet controller thinks it is set to,
and change the settings.
[root@sflory cujo]# mii-tool -v eth0
eth0: negotiated 100baseTx-FD, link ok
product info: vendor 00:aa:00, model 51 rev 0
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
[root@sflory cujo]# ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: puag
Wake-on: g
Link detected: yes
[root@sflory cujo]#
-- Once you have their hardware. Never give it back. (The First Rule of Hardware Acquisition) Sam Flory <sflory@rackable.com>- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Jul 23 2003 - 22:00:47 EST