monitoring packet rate & softirq

Andrwe · 2011-12-19 18:52:13

Hi,

on a server running Debian Squeeze and keepalived I ran into some issues.
If I produce many requests against the server the amount of softirqs increases very fast until 1 CPU is at 100%.

I want to investigate this problem but I don't know of a tool to monitor the paket rate and the IPs causing it.
Also I need for this investigation a way to examine the softirqs, what's causing them, what are they waiting for and so on.

Does anyone of you know of such tools?

Kind regards,
Andrwe

marvn · 2011-12-19 21:27:11

you can use iftop as a network monitor

Andrwe · 2011-12-19 21:43:14

marvn wrote:

you can use iftop as a network monitor

Unfortunately iftop isn't able to monitor the packet rate but only the bandwidth.

There is quite a difference between both.

A network card can be able to process terabit/s but that doesn't mean it can process terapackets/s.
And if your system can't handle the packet rate it gets cpu load because of softirqs very fast.
While too much bandwidth is just cut at the maximum which can be handled and that can cause slowly increasing cpu load.

ZekeSulastin · 2011-12-20 00:41:20

I know iptraf-ng will show packet rate and such ... maybe it'll do what you need?

Andrwe · 2011-12-22 21:25:22

Hi,

I've found 2 tools which are good to use:
ntop (in community)
jnettop (in AUR)

Jnettop is nice for a current view and ntop for a long time analysis.
If you use jnettop on a load balancer with >500 MBit / >40000 Pkts/s traffic then you have to disable content filtering an IP resolving.

Arch Linux

#1 2011-12-19 18:52:13

monitoring packet rate & softirq

#2 2011-12-19 21:27:11

Re: monitoring packet rate & softirq

#3 2011-12-19 21:43:14

Re: monitoring packet rate & softirq

#4 2011-12-20 00:41:20

Re: monitoring packet rate & softirq

#5 2011-12-22 21:25:22

Re: monitoring packet rate & softirq

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