web: flamegraph: show filename in tooltip

[mhansen]

Forked off from #649 (comment)

What version of pprof are you using?

7fe48b4

What did you do?

Open the flamegraph view in the web browser:

What did you expect to see?

Filename in the tooltip -- in this case I used -roottag thread to add synthetic stack frames to the root of the trace, with the Filename = "thread", so help label the node.

What did you see instead?

No filename.

Fixing this might require moving to a DOM-element for the tooltip, I'm not sure if browsers natively support multiline tooltips?

[mhansen]

Looks like there's options for an HTML-based tooltip in the latest d3-flamegraph: https://github.com/spiermar/d3-flame-graph#tooltip

[mhansen]

The filename isn't passed as JSON to the FlameGraph yet, we'll want to add it to the {{.FlameGraph}} template variable to access it in the client.

[mhansen]

Can't just pass node.Info.File to {{.FlameGraph}} as .File doesn't seem to be filled in yet, it seems empty in my test profiles.

[aalexand]

@mhansen RE empty filenames: can you try passing -filefunctions flag to pprof?

[mhansen]

Thanks Alexey, -filefunctions works pretty well! Works on the synthetic tag filenames too.

[mhansen]

I'm still wondering if we could put the filename in the tooltip by default, but I could go either way on it (this at least solves my immediate problem of how to demo tagroot in a blog post).

[aalexand]

I think we went back and forth on having -functions vs. -filefunctions as the default granularity in the past, so I'm not too enthusiastic about flipping the default. I could be convinced, but this might break some users.

[aalexand]

#106 is when we changed this.

We could force a different default in the flame graph generation perhaps, though we'll need to make sure this only changes the defaults and choosing a different granularity on the command line is still possible (e.g. -addresses etc).

[aalexand]

@mhansen For the blog post, you could simply have the instructions there as "Run pprof with -filefunctions flag"?

[mhansen]

I don't think we should flip the defaults. I'm just wondering about maybe sending the filename and the function name down in the JSON, and making a richer tooltip that shows the filename+function.

…

On Sat, 16 Oct 2021 at 08:28, Alexey Alexandrov ***@***.***> wrote: #106 <#106> is when we changed this. We could force a different default in the flame graph generation perhaps, though we'll need to make sure this only changes the defaults and choosing a different granularity on the command line is still possible (e.g. -addresses etc). — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#655 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAZYOLK3DV5CFPZRYJA53TUHCMGFANCNFSM5FECQC5A> .

[mhansen]

The picture in my mind is something like what Firefox Profiler does: a baby step towards a richer tooltip that shows the filename (and doesn't mean the flamegraph has to also show the filename). Could start with the filename then grow that tooltip into more information like self & total time.