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ddrown / chrony-graph

Generate Graphs from chrony logs
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Linlog cuts off extremes #9

Open MarcelWaldvogel opened 2 years ago

MarcelWaldvogel commented 2 years ago

I like the linlog layout, thanks @inkdot7!

However, it should ensure that a ytic beyond the maximum is set, to make the value visible. For example, in the following graph, the downward peak goes to -16 seconds (the time it took for the Raspi to reboot/resync time).

grafik

In the next graph, the ±RTT/2 lines are not visible at all and entirely cut off.

grafik

I expect that the outermost part becomes logarithmic; RTT/2 is ~100 ms.

It would be really great if these minor glitches could be improved.

inkdot7 commented 2 years ago

In the first graph, there are two problems, correct?:

Second graph:

It might be helpful with a dataset that reproduces the issues.

MarcelWaldvogel commented 2 years ago

Yes, that seems to be about it.

I have put the files (state: UTC midnight) into https://gpstime.trifence.ch/statistics.{GPS,200.160.7.197}. I hope they help (and thousand thanks for looking into it!)

In case the result is gnuplot-dependent: V5.4 patchlevel 1 on Debian bullseye (Raspberry Pi).

MarcelWaldvogel commented 2 years ago

I wanted to change the percentile of the linear range to tune some graphs and I noticed two things:

  1. linscalelimit seems to assume a one-sided graph (from 0 to some +x), however, for two-sided graphs (-y to +x) it might be useful to have a lower and upper linscalelimit (maybe even symmetric around y=0)
  2. I've had graphs where the tics were 10, 20, 200; however, the values did not go above 30, i.e., even though the percentile-based logic requires the outermost range to be logarithmic, not more space would be used by keeping that linear. Can we augment the logic as follows?
    • If none of the values is greater than 1.5 * linscalelimit, do not switch to logarithmic mode
    • (The downside: This probably requires an additional pass (or a third/fourth return value to keep track of), as this decision should only be made after all the input files have been analyzed.)