FlameGraph: The displayed samples are wrong

[simonswine]

We currently base the displayed samples on the total sample values, rather than the sample count.

That leads to wrong values being displayed. An example is this:

As this is a Golang CPU profiler, the standard sampling rate is 100 samples per seconds, which would mean that is the values we would expect:

1.01 seconds / 101 samples

There is more detail in the Pyroscope issue https://github.com/grafana/pyroscope/issues/3340, but it would be good to respect sampleRate in the metadata of the /render endpoint:

• Whenever sampleRate is 0 or null we should no longer show samples (also in the tooltip)
• Whenever sampleRate is set to > 0 we should multiply the sampleRate with the totalTicks or totalValue (in the tooltip).

[simonswine]

So we decided to go with a solution that accepts a factor in a field called sampleRate. In case this field is missing or 0, we should no longer show the "x samples" line in the tool tip or the "| x samples" in the top field.