[gentoo-user] Network collisions

[gentoo-user] Network collisions

[Dave Oxley]

Hi all,

I have two Gentoo machines (specified as Server and Client for ease). 
The server networking is working fine, but the client cannot receive 
without lots of collisions. The speeds I get are:
Server -> Client (i.e. receive) 170.3Kb/sec
Client -> Server (i.e. transmit) 7.383Mb/sec
The cards of both machines are running half duplex. If I try to force 
them to full duplex with (ethtool -s eth0 speed 100 duplex full autoneg 
off) then all I get is errors in ifconfig. The module used for 
networking on the client is 8139too. Can anybody help me with this?

Some information:
Server:
lspci -v:
0000:02:09.0 Ethernet controller: Atheros Communications, Inc. AR5212 
802.11abg NIC (rev 01)
        Subsystem: Netgear: Unknown device 4900
        Flags: bus master, medium devsel, latency 64, IRQ 5
        Memory at feae0000 (32-bit, non-prefetchable) [size=64K]
        Capabilities: [44] Power Management version 2

ethtool eth0:
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Half
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: g
        Wake-on: d
        Current message level: 0x00000037 (55)
        Link detected: yes

Client:
lspci -v:
0000:02:03.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL-8139/8139C/8139C+ (rev 10)
        Subsystem: Micro-Star International Co., Ltd.: Unknown device 093c
        Flags: bus master, medium devsel, latency 64, IRQ 201
        I/O ports at df00 [size=256]
        Memory at fdcff000 (32-bit, non-prefetchable) [size=256]
        Expansion ROM at fde00000 [disabled] [size=64K]
        Capabilities: [50] Power Management version 2

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: Half
        Port: MII
        PHYAD: 32
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: pumbg
        Wake-on: d
        Current message level: 0x00000007 (7)
        Link detected: yes

ifconfig:
eth0      Link encap:Ethernet  HWaddr 00:11:09:FA:E4:64
          inet addr:192.168.1.157  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:9835 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7422 errors:0 dropped:0 overruns:0 carrier:0
          collisions:783 txqueuelen:1000
          RX bytes:11748803 (11.2 Mb)  TX bytes:659065 (643.6 Kb)
          Interrupt:201 Base address:0x4000

Cheers,
Dave.
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Re: [gentoo-user] Network collisions

[Mark Knecht]

On 10/3/05, Dave Oxley <dave@daveoxley.co.uk> wrote:
> Hi all,
>
> I have two Gentoo machines (specified as Server and Client for ease).
> The server networking is working fine, but the client cannot receive
> without lots of collisions. The speeds I get are:
> Server -> Client (i.e. receive) 170.3Kb/sec
> Client -> Server (i.e. transmit) 7.383Mb/sec
> The cards of both machines are running half duplex. If I try to force
> them to full duplex with (ethtool -s eth0 speed 100 duplex full autoneg
> off) then all I get is errors in ifconfig. The module used for
> networking on the client is 8139too. Can anybody help me with this?
>

I just recently had a problem like this. In my case the switch
everything was plugged into got in some strange state and power
cycling the switch fixed the problem.

Hope this helps,
Mark

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Re: [gentoo-user] Network collisions

[Uwe Thiem]

On 04 October 2005 07:28, Dave Oxley wrote:
> Hi all,
>
> I have two Gentoo machines (specified as Server and Client for ease).
> The server networking is working fine, but the client cannot receive
> without lots of collisions. The speeds I get are:
> Server -> Client (i.e. receive) 170.3Kb/sec
> Client -> Server (i.e. transmit) 7.383Mb/sec
> The cards of both machines are running half duplex. If I try to force
> them to full duplex with (ethtool -s eth0 speed 100 duplex full autoneg
> off) then all I get is errors in ifconfig. The module used for
> networking on the client is 8139too. Can anybody help me with this?

Replace the client's NIC.

Uwe

-- 
95% of all programmers rate themselves among the top 5% of all software 
developers. - Linus Torvalds

http://www.uwix.iway.na (last updated: 20.06.2004)
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Re: [gentoo-user] Network collisions

[Dave Oxley]

Hi Mark,

Thanks for the reply. Unfortunately, I had already tried power cycling 
my hub and it made no difference.

Cheers,
Dave.

Mark Knecht wrote:

>On 10/3/05, Dave Oxley <dave@daveoxley.co.uk> wrote:
>  
>
>>Hi all,
>>
>>I have two Gentoo machines (specified as Server and Client for ease).
>>The server networking is working fine, but the client cannot receive
>>without lots of collisions. The speeds I get are:
>>Server -> Client (i.e. receive) 170.3Kb/sec
>>Client -> Server (i.e. transmit) 7.383Mb/sec
>>The cards of both machines are running half duplex. If I try to force
>>them to full duplex with (ethtool -s eth0 speed 100 duplex full autoneg
>>off) then all I get is errors in ifconfig. The module used for
>>networking on the client is 8139too. Can anybody help me with this?
>>
>>    
>>
>
>I just recently had a problem like this. In my case the switch
>everything was plugged into got in some strange state and power
>cycling the switch fixed the problem.
>
>Hope this helps,
>Mark
>
>  
>
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Re: [gentoo-user] Network collisions

[kashani]

Dave Oxley wrote:
> Hi Mark,
> 
> Thanks for the reply. Unfortunately, I had already tried power cycling 
> my hub and it made no difference.
> 

	Hubs only support half-duplex which pretty much guarantees collisions. 
Is it really a hub or are you just referring to yous switch as a hub?

	Assuming you have a switch I'd attempt to set full duplex without 
turning autoneg off... that sometimes helps. You might also try emerging 
the unstable ethtool3 as it supports more cards then the default 
ethtool2 and has some bug fixes. Some cards work better with mii-diag so 
you might try that as well.

kashani
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Re: [gentoo-user] Network collisions

[Dave Oxley]

Ah right. I did not know that!

Yeah, its a hub. I'll stop trying to set it to full duplex now. I still 
have a problem though, the collision rate is 11-12% when copying to the 
client and the performance is terrible:
Copying from Server to Client (i.e. receive) 170.3Kb/sec
Copying from Client to Server (i.e. transmit) 7.383Mb/sec

It is 40 times quicker in one direction than the other. Can you give me 
a hint where to go from here.

Cheers,
Dave.

kashani wrote:

> Dave Oxley wrote:
>
>> Hi Mark,
>>
>> Thanks for the reply. Unfortunately, I had already tried power 
>> cycling my hub and it made no difference.
>>
>
>     Hubs only support half-duplex which pretty much guarantees 
> collisions. Is it really a hub or are you just referring to yous 
> switch as a hub?
>
>     Assuming you have a switch I'd attempt to set full duplex without 
> turning autoneg off... that sometimes helps. You might also try 
> emerging the unstable ethtool3 as it supports more cards then the 
> default ethtool2 and has some bug fixes. Some cards work better with 
> mii-diag so you might try that as well.
>
> kashani

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Re: [gentoo-user] Network collisions

[Jonathan Wright]

Dave Oxley wrote:
> Ah right. I did not know that!
> 
> Yeah, its a hub. I'll stop trying to set it to full duplex now. I still 
> have a problem though, the collision rate is 11-12% when copying to the 
> client and the performance is terrible:
> Copying from Server to Client (i.e. receive) 170.3Kb/sec
> Copying from Client to Server (i.e. transmit) 7.383Mb/sec
> 
> It is 40 times quicker in one direction than the other. Can you give me 
> a hint where to go from here.

Some hubs don't like having different sets of ports and it's a repeater, 
not an 'intelligent' routing system. If you're going to try and set the 
cards to FD you may want to try disconnecting them all and connecting 
them all one at a time once you have forced the card to FD.

Admitidly, I don't know why it would be faster one way than the other. 
I'm wondering if that's a cable issue (partially damaged cable causing a 
small capacitance effect). Do you get the same effect when you swap the 
cables over?

-- 
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                                            ~ www.djnauk.co.uk
--
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  up 4 days,  3:12,  3 users,  load average: 0.19, 0.36, 0.58
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  aren't burdened with children."

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[gentoo-user] Re: Network collisions

[James]

Dave Oxley <dave <at> daveoxley.co.uk> writes:


> Yeah, its a hub. I'll stop trying to set it to full duplex now.

> It is 40 times quicker in one direction than the other. Can you 
> give me a hint where to go from here.

Try connecting the 2 systems  with only a 'cross-over cable' run the applications
and make measurements. If this results in an increase in the bandwidth 
in either direction, you may want to put systems back on the hub, and 
have a third system run ethereal. Look at your data traffic and see 
if anythingelse is using the bandwidth from either of these 2 system 
or what else is plug into the hub/switch.

Is the hub a 10Mbps only hub/switch, check that. On 10 Mbps ethernet 
hubs,you can never reach the full 10 Mbps, in fact with many systems 
chattering,the practical throughput is marginally around 33%.

If when you are on the cross over cable and you get similar poor 
results,then the problem may be in the ethernet driver code, 
kernel, irq settings or
some other low level part of the kernel/modules, especially if 
you get the same skewed results with several different 
applications moving data between the systems. But, if when
 you move data between these 2 isolated system, and 
get different bandwidth performance semantics, then the problem 
is most likely between the applications or a bottleneck in the 
application code (poor data structure for example).

Make sure you computers are not resource limited, thus blocking 
the processthat you are running to move the data. Top and ntop 
are just a few toolsto help track down these sort of issues.

Sadly, you may have a complex mix of part or all of these 
aforementioned issues... 

hth,
James

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Re: [gentoo-user] Network collisions

[Dave Oxley]

Its on board the motherboard. I could put a second NIC in but I don't 
want to waste the pci slot. This is an HTPC.

Dave.

Uwe Thiem wrote:

>On 04 October 2005 07:28, Dave Oxley wrote:
>  
>
>>Hi all,
>>
>>I have two Gentoo machines (specified as Server and Client for ease).
>>The server networking is working fine, but the client cannot receive
>>without lots of collisions. The speeds I get are:
>>Server -> Client (i.e. receive) 170.3Kb/sec
>>Client -> Server (i.e. transmit) 7.383Mb/sec
>>The cards of both machines are running half duplex. If I try to force
>>them to full duplex with (ethtool -s eth0 speed 100 duplex full autoneg
>>off) then all I get is errors in ifconfig. The module used for
>>networking on the client is 8139too. Can anybody help me with this?
>>    
>>
>
>Replace the client's NIC.
>
>Uwe
>
>  
>
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Re: [gentoo-user] Re: Network collisions

[Dave Oxley]

Ok, I've fixed the problem. I've plugged both systems into my router 
(which is a switch) and they are working fine now. There is obviously a 
bug in the 8139too driver. I'll have to live with the long cables going 
to the switch for the time being though!!

Cheers for everyones help.
Dave.

James wrote:

>Dave Oxley <dave <at> daveoxley.co.uk> writes:
>
>
>  
>
>>Yeah, its a hub. I'll stop trying to set it to full duplex now.
>>    
>>
>
>  
>
>>It is 40 times quicker in one direction than the other. Can you 
>>give me a hint where to go from here.
>>    
>>
>
>Try connecting the 2 systems  with only a 'cross-over cable' run the applications
>and make measurements. If this results in an increase in the bandwidth 
>in either direction, you may want to put systems back on the hub, and 
>have a third system run ethereal. Look at your data traffic and see 
>if anythingelse is using the bandwidth from either of these 2 system 
>or what else is plug into the hub/switch.
>
>Is the hub a 10Mbps only hub/switch, check that. On 10 Mbps ethernet 
>hubs,you can never reach the full 10 Mbps, in fact with many systems 
>chattering,the practical throughput is marginally around 33%.
>
>If when you are on the cross over cable and you get similar poor 
>results,then the problem may be in the ethernet driver code, 
>kernel, irq settings or
>some other low level part of the kernel/modules, especially if 
>you get the same skewed results with several different 
>applications moving data between the systems. But, if when
> you move data between these 2 isolated system, and 
>get different bandwidth performance semantics, then the problem 
>is most likely between the applications or a bottleneck in the 
>application code (poor data structure for example).
>
>Make sure you computers are not resource limited, thus blocking 
>the processthat you are running to move the data. Top and ntop 
>are just a few toolsto help track down these sort of issues.
>
>Sadly, you may have a complex mix of part or all of these 
>aforementioned issues... 
>
>hth,
>James
>
>  
>
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