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I'm looking for an utility that could show me how much of a bandwidth each process are using. It should just print the data and exit as I want to feed that list into conky.

3 Answers 3

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You can try NetHogs.

NetHogs is a small 'net top' tool. Instead of breaking the traffic down per protocol or per subnet, like most tools do, it groups bandwidth by process. NetHogs does not rely on a special kernel module to be loaded. If there's suddenly a lot of network traffic, you can fire up NetHogs and immediately see which PID is causing this. This makes it easy to indentify programs that have gone wild and are suddenly taking up your bandwidth.

NetHogs_Screenshot

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  • Almost exactly what I need but it just doesn't work :(
    – vava
    Aug 31, 2009 at 17:24
  • Well, what doesn't work? Any errors? Doesn't it start at all? Console output?
    – Milde
    Sep 1, 2009 at 7:14
  • it not works with ipv6
    – zb'
    May 29, 2014 at 22:20
  • You have to run it as root. Promiscous mode is recommended. sudo nethogs -p eth2. You have to specify your ethernet if it is not eth0 by default. Mar 13, 2015 at 5:39
  • @vava There's a problem with the one in the repo, it's fixed in 0.8.1 but you have to build from source (which is extremely easy). See this post: askubuntu.com/questions/726601/…
    – Matthew
    Jul 10, 2016 at 5:22
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There is quite a few listed here.

My favorites however remain iftop and tcpdump. Wireshark is also a very good option.

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  • I have ethical issues with Wireshark, if not alone on the network... Unless you have a way to make it probe only the localhost, in which case I'm interested.
    – Gnoupi
    Aug 31, 2009 at 14:18
  • 5
    If you don't enable promiscuous mode it should only capture traffic directed to your host.
    – Amok
    Aug 31, 2009 at 15:57
  • Huh, not one of those utilities can tell me which process are using most bandwidth and that's what I'm after.
    – vava
    Aug 31, 2009 at 17:25
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Try atop ... to get the most out of it you may have to enable some additional kernel patches (I/O accounting patches).

If atop isn't an option then use netstat -anp --inet (as root) to provide a listing of which TCP/UDP ports are in use by which processes (or possibly use lsof for that). From there simply iterate over each process that's got an open socket and either attach to it using ltrace -S or strace to look at the reads, writes, sends and receives, or use tcpdump with a filter specifying your local IP address(es) and the TCP/UDP ports that were listed.

atop is certainly the most convenient of these ... if you have it and the necessary kernel support installed. In the past I've had customers and employers set up special systems (different from their production images) for the sole purpose of supporting I/O profiling using atop. However these other techniques will get you there.

I'm sure we could also do something using SystemTap ... but I don't know of any easy pre-cooked recipes for doing this. SystemTap is very much a programming analysis tool.

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  • if you just want to know which process is hogging the network, not the real bandwidth used, you can just use netstat -anp --inet, and check the Recv-Q and Send-Q columns
    – golimar
    Aug 16, 2018 at 14:53

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