packets being dropped in IP stack but no error counts incrementing?
I've been doing some testing on 2.4.18 and I'm seeing an interesting problem.
I have a test tool that simulates bursty UDP traffic by sending a bunch of
messages and then delaying a while. If I leave the receiving udp socket at its
normal size, then I can get a significant number of messages just vanishing between the ethernet driver and the userspace socket. The driver rx count shows that all packets were received, but the userspace program doesn't get all of them. netstat/ifconfig/iproute2 rx dropped counts do not increase.
Is this design intent, are we messing a counter increment when dropping packets, or am I not looking at the right counter for these numbers?
Thanks,
Chris
Signature · 4 lines
Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: [email protected]
I am not sure the UDP drop counters are available. If you do find them, I'm interested in them too!
Quoted 17 lines · Chris Friesen
I've been doing some testing on 2.4.18 and I'm seeing an interesting problem.
I have a test tool that simulates bursty UDP traffic by sending a bunch of
messages and then delaying a while. If I leave the receiving udp socket at its
normal size, then I can get a significant number of messages just vanishing between the ethernet driver and the userspace socket. The driver rx count shows that all packets were received, but the userspace program doesn't get all of them. netstat/ifconfig/iproute2 rx dropped counts do not increase.Is this design intent, are we messing a counter increment when dropping packets, or am I not looking at the right counter for these numbers?
Thanks,
Chris
Signature · 3 lines
Ben Greear <[email protected]> <[email protected]> President of Candela Technologies Inc http://www.candelatech.com ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear
Quoted 3 lines · Ben Greear
I am not sure the UDP drop counters are available. If you do find them, I'm interested in them too!
Well, I've found an entry in /proc that has some information. The entry is:
/proc/net/softnet_stat
The first two columns are:
total
dropped
In this case, dropped is the number of messages dropped due to the softnet_data queue being full. I have actually hit this under high load.
I'm still looking for socket/protocol specific stuff though.
Chris
Signature · 4 lines
Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: [email protected]
Quoted 4 lines · Chris Friesen
Quoted 3 lines · Ben Greear
I am not sure the UDP drop counters are available. If you do find them, I'm interested in them too!
You are using netstat -s/cat /proc/net/snmp and ifconfig/cat /proc/net/dev