Calculate and display Jitter about trippy

[trkelly23]

I am taking this issue on my existing fork. I will be working towards a PR for review by EOW.

[trkelly23]

Here's a proposal for the feature after taking a look at the code. The calculation requires at least 2 round trips to be completed for each hop. The millis Duration value from consecutive hops (HOPn - HOPn-1) results in jitter duration.
Calc: Jitter = RTTn - RTTn-1
RTT = Round trip time

1. Add --jitter -j option for the command line. Starts up in jitter display mode.
2. Headings will have a "J" prepended in the display.
3. Add values to any reporting like csv.
4. Might need jitter mode to Mode enum tui-jitter.
5. Stretch - When tui display is running pressing "j" will switch to jitter mode. This comes from having used mtr in the passed.

Am I overthinking it should I scale it back?

[fujiapple852]

@trkelly23 thanks for picking this up!

Add --jitter -j option for the command line. Starts up in jitter display mode.
Headings will have a "J" prepended in the display.

Which headings would be prefixed? I had imagined these jitter related values as additional columns in the hops table, is that what you are proposing?

A mockup of what I envisioned:

╭Hops───────────────────────────────────────────────────────────────────────────────────────────╮
│#   Host          Loss% Snt   Recv  Last  Avg   Best  Wrst  StDev  Jttr  Javg  jmax  Jint  Sts │
│2   10.76.194.68  0.0%  118   118   0.8   1.3   0.5   22.0  2.7    xxx   xxx   xxx   xxx   🟢  │

Is the proposal that these columns would be calculated and/or shown only if the --jitter (-j) flag is specified? While I think that is fine, what do you think about doing #757 first or along with this change so that the selection of columns to show can be more flexible?

Add values to any reporting like csv.

Yes that makes sense, we should add to all report modes.

Might need jitter mode to Mode enum tui-jitter.

Right, similar to --tui-as-mode we may want a --tui-jitter-mode or similar to control how jitter is displayed in the Tui. It could be as simple as a bool to turn jitter display on/off or an enum to give finer control of which columns are shown. Just to be clear, I don't think a new --mode tui-jitter is needed here however.

When tui display is running pressing "j" will switch to jitter mode. This comes from having used mtr in the passed.

Yes that would be useful. It shouldn't be to difficult to add as there are several other such things in the Tui already, such as pressing z to toggle the AS display mode. I can always help you with this part if needed.

The calculation requires at least 2 round trips to be completed for each hop. The millis Duration value from consecutive hops (HOPn - HOPn-1) results in jitter duration.
Calc: Jitter = RTTn - RTTn-1
RTT = Round trip time

I just had a look in mtr and, whilst we don't need to restrict ourselves to doing things the same way, it does serve as a useful reference point.

It allows specifying these additional (non-default) columns:

Jttr: Current Jitter
Javg: Jitter Mean/Avg.
Jmax: Worst Jitter
Jint: Interarrival Jitter

It would be useful to look at how these are calculated and aim to emulate the logic here. From a quick glance they seem more complex than simply RTTn - RTTn-1 though I confess statistics is not my area of expertise!