Lost packets

QNX DEVELOPERS Realtime and Embedded
1

Hello Friends.

I had very strange issue recently. I have two embedded computers (vp7 and vp9). Vp9 machine have intel i82544 network adapter , on the vp7 machine - pcnet32.
Qnx version 6.4.0.

On the vp9 machine I don’t lost udp packets, but on vp7 I regulary lost packets.

If I invoke “pidin -p io-pkt-v4-hc mem” I see , that pcnet32 network driver (devn-pcnet.so) is work via devnp-shim.so. But on vp9 machine network adapter (devnp-i82544.so) work without devnp-shim.so. May be this is a core of the problem??? And how I can play with network adapter options???

2

How do you detect packets are lost, via nicinfo, via netstat -s or through your application. Packets can be lost at various stages of their travel

3

I invoke tcpdump on vp7 machine and invoke tcpdump on the send side. On send side I see certain packet , but on the receive side (vp7 machine) I don’t .

4

netstat -s say that there is no problem)))))))))) , nicinfo also

5

n theory if nicinfo doesn’t report lost packet and netstat’s -s " UDP dropped due to full socket buffers" is at 0, then it could be :

  • A bug a 6.4.0
  • A hardware problem
  • tcpdump is throwing out packet
  • The send side isn’t really sending them
  • Something else I haven’t though of ;-)
6

How about cabling? Try switching the cables and see if the problem moves or stays where it is.

7

The apps may also be sending data to fast and not making it to the wire.

8

I will try to switch cable and say about results.

Our traffic is light. How I can to increase needed buffers in network card??? And what is the needed buffers in network stack??? Tx and Rx descriptors??? Or buffers in the io-pkt???

9

I forget to say THANK YOU for attention to my problem))))

10

Forget to say that after autonegatiation stage pcnet32 adapter (in the vp7 machine) work in half-duplex mode. Maybe this key???

11

I don’t think you can increase a network card’s buffers. There might be parameters for io-pkt, but I don’t think that’s your problem. The half-duplex suggests either a cable or a hub problem. If your cards are 100TX but the cables are not CAT5 (at least) that might cause the problem.

12

I notice one thing when my application invoked. If I run command “sloginfo -w -c” then I have three times in second
message → “pcnet memory error”.

Maybe someone have pcnet32 network adapter sources. What is the case when “pcnet memory error” message
generated???

I invoke “top” command and see that 28M of memory are available, i.e. there is no memory problem.

13

Maschoen. Where are you??? ))))))))))))

14

I don’t know what that error means. It sounds like a hardware problem, either something bad on the card, or an incompatibility.

15

How I can get pcnet sources???

16

You would have to talk with your QNX representative.

17

Maschone, you captain evidence))))))))))))))))))

18

You have to contact QNX.

19

I send message to info@qnx.com , but threre is no answer. ((((((((((((((((((

20

Have you considered the date today?