Modify collectd/RRDtool to display bps instead of B/s

[feliciano]

I installed RRDtool feeded by collectd (on 22.03.3). I notice the network graphs are presented in Bytes/s and Packets/s as gathered from the tracked interfaces, but when talking about bandwidth people usually talks about Mbps more than KB/s.

I read a @dlang comment on an old thread:

@dlang

rrdtool lets you specify units, including doing math on the data as it
arrives to convert it to your desired units, go through the rrdtool docs for
examples of how to do this.

I've read some collectd and RRDtool docs, and I've noticed there is the Target option to scale (let's say to multiply x8) a measurement, so we could use that feature to get bps. Then we may also need to modify the Y axis label as well.

The thing is I haven't found a confirmation on whether we can do those changes for OpenWrt by means of some configuration file(s), or we would need to go through the source code (which I may do in the future, but at the moment I prefer a quick solution).

[hnyman]

@feliciano

I haven't found a confirmation on whether we can do those changes for OpenWrt by means of some configuration file(s), or we would need to go through the source code

source code.

Quickest solution is probably to apply a RPN calculation to the data in the LuCI graph config source.

Just like here a value is multiplied by 100 to turn 0.02 to 2 (for %).

openwrt/luci/blob/master/applications/luci-app-statistics/htdocs/luci-static/resources/statistics/rrdtool/definitions/ping.js#L41

[feliciano]

@hnyman

transform_rpn: "100,*"

Based on that, I modified interface.js adding transform_rpn: "8,*" to var traffic = {...} and modified the legend, title and labels (not using Firefox).