FR: Documentation of timeline feature

[pallaswept]

Please forgive the newbie question, but I can't seem to find any documentation which describes the meaning of these blue rectangles below the CPU usage graph:

I'm sure that the matrix room would be able to help me out, but it would also be nice if this part of the timeline were also explained in the docs

Thanks!

┆Issue is synchronized with this Jira Task

[canova]

Thanks for the bug report!

Each of these boxes mean a single stack "sample" in the timeline. These boxes are there to indicate in which exact time a sample is sampled. You might see more clearly if you zoom in enough in a profile time range.

But you are right about it not being clear enough. We actually got a few more questions similar to yours, so you are not alone there. We should definitely document it.

But besides the documentation, I would prefer to make it clear directly inside the app (if we can) so our users won't have to look at the documentation. I actually had a half-baked patch that adds "sample tooltips" when you hover over there. The tooltips look like this when you hover over them:

Do you think it would've helped you understand if we had these?

[pallaswept]

Do you think it would've helped you understand if we had these?

Absolutely!

I had my suspicions about this but when I wanted to be sure, the docs left me wondering, so I sent this... Just as you said, shortly afterwards, I zoomed in further and realised the stacks were only changing there, thus those must show each sample. But if I'd had that hover effect which you showed, I think I would have figured that out before I zoomed in to the microseconds :)

[canova]

Thanks for the feedback! I opened #5298 to add the tooltips to the sample graph. Hopefully that will be helpful for your case and in case other people are confused as well.

Let's keep this issue open still for the documentation changes.