On Fri, 26 Feb 2016, Christos Zoulas wrote:
Date: Fri, 26 Feb 2016 14:52:46 +0000 (UTC)
From: Christos Zoulas <[email protected]>
To: [email protected]
Subject: Re: high cpu load with tcpdump
In article <pine.neb.4.64.1602261452000.28...@6bone.informatik.uni-leipzig.de>,
<[email protected]> wrote:
Hello,
On my router tcpdump uses always 100% CPU.
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND
3403 _tcpdump 38 0 19M 3016K RUN/6 0:24 98.08% 70.02% tcpdump
0 root 0 0 0K 1182M CPU/7 49:35 0.00% 3.76% [system]
The problem also occurs when tcpdump is listening on an interface
with no network traffic. Therefore, it can not be a load problem.
The problem does not occur on all interfaces.
ixg(0|1), bnx(0|1) and tap(0|1) are affected.
lo0, stf0 and vlan* are not affected.
System is: NetBSD 7.0_STABLE
Any idea what could be the problem?
Thank you for your efforts.
ktrace please?
christos
...
5015 1 tcpdump 1456559035.621583576 CALL read(3,0x7f7ff7b16000,0x80000)
5015 1 tcpdump 1456559035.621593842 RET read -1 errno 35 Resource
temporarily unavailable
5015 1 tcpdump 1456559035.621595938 CALL read(3,0x7f7ff7b16000,0x80000)
5015 1 tcpdump 1456559035.621598033 RET read -1 errno 35 Resource
temporarily unavailable
5015 1 tcpdump 1456559035.621599849 CALL read(3,0x7f7ff7b16000,0x80000)
5015 1 tcpdump 1456559035.621601944 RET read -1 errno 35 Resource
temporarily unavailable
5015 1 tcpdump 1456559035.621603690 CALL read(3,0x7f7ff7b16000,0x80000)
5015 1 tcpdump 1456559035.621605785 RET read -1 errno 35 Resource
temporarily unavailable
5015 1 tcpdump 1456559035.621607601 CALL read(3,0x7f7ff7b16000,0x80000)
5015 1 tcpdump 1456559035.621609626 RET read -1 errno 35 Resource
temporarily unavailable
...
There are more than 150,000 read operations per second.
When a data packet is sent or received by the interface, the data packet
is displayed correctly.
Regards
Uwe
