[Iftop-users] linear scale calibration problem

[Markus Koschany]

Hello,

I am hereby forwarding Debian bug: 922427

https://bugs.debian.org/922427

In a nutshell: The initial linear scale of the bandwidth is often much
wider than the actual available network bandwidth, leading to bar graphs
that are quite narrow. There are existing options like -L and -m that
can mitigate the problem but still the initial scaling can assume much
more bandwidth than is actually available. Maybe avoiding to resize the
scale to more than 120% of the max bandwidth seen, would solve the problem.

Regards,

Markus


Here is the complete bug report for your convenience:


The way iftop calibrates its linear scale, it seems to often make the
scale much wider than the actual available network bandwidth, leading to
bar graphs that are quite narrow, often 1 character wide or 0 characters
wide, for network connections that are pushing relatively a lot of
traffic. This makes it not very useful to spotting at a glance what is
eating bandwidth.

I generally press L to switch to log scale, which avoids the problem,
showing big wide bars.

For example, I've started iftop when the network is nearly completely
idle. It picked a scale 1KB-8KB, which is fine. Then I started a
download, which ran at 300-615KB/s. This causes the scale to change to
2MB-12MB. Since my wifi connection happens to be limited to around
1MB/s, this guarantees bars will never be more than a few characters
wide.

Here's how that displays after downloading for several minutes:

                2.38MB          4.77MB           7.15MB          9.54MB
   11.9MB
└───────────────┴───────────────┴────────────────┴───────────────┴────────────────
darkstar.kitenet.:51000 => kitenet.net:ssh          849KB  6.87KB
5.68KB  5.95KB
###                     <=                         57.7MB   478KB
381KB   410KB
──────────────────────────────────────────────────────────────────────────────────
TX:             cum:   1.10MB   peak:   9.33KB    rates:   7.07KB
4.95KB  6.71KB
RX:                    72.0MB            648KB              466KB
325KB   457KB
TOTAL:                 73.1MB            657KB              473KB
330KB   463KB

("RX:" is highlighted and I've marked the top highlight using "###".)