add flame chart mode

[AnderEnder]

Closes #23

[codecov-io]

Codecov Report

Merging #125 into master will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #125      +/-   ##
==========================================
+ Coverage   90.27%   90.30%   +0.02%     
==========================================
  Files          16       16              
  Lines        2232     2238       +6     
==========================================
+ Hits         2015     2021       +6     
  Misses        217      217              

Impacted Files	Coverage Δ
src/flamegraph/merge.rs	94.79% <100.00%> (+0.05%)	⬆️
src/flamegraph/mod.rs	96.46% <100.00%> (+0.06%)	⬆️

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[jonhoo]

I haven't forgotten about this, but would like to see the response to #23 (comment) first, as I think it means that these charts don't actually turn out useful.

[jonhoo]

Wow, sorry, I dropped the ball on this even though the referenced comment has now seen some further discussion! I still wonder if it'd be useful to have a "non-collapsing" folder that just turns stacks into the right line format for the flamegraph tool to consume, but I think this is useful even without that (and such a tool should probably be a separate PR anyway). Let me update my review of this, and hopefully we should be able to land this without too much trouble!

[jonhoo]

@That3Percent want to give this PR a shot and see whether it produces the kind of output you're after?

[That3Percent]

I gave this a try and got an error: Io(Custom { kind: InvalidData, error: "unsorted input lines detected" })

Using options:

let mut options = flamegraph::Options {
        count_name: "ns".to_owned(),
        hash: true,
        flame_chart: true,
        ..Default::default()
    };

And the following data, which I hope is correct:
flames.txt

[jonhoo]

Ohh, interesting, yeah, that error will definitely need to be suppressed for a flame chart. @AnderEnder it's here:

inferno/src/flamegraph/merge.rs

Lines 131 to 136 in 0bf9331

	if prev_line > line {
	return Err(quick_xml::Error::Io(io::Error::new(
	io::ErrorKind::InvalidData,
	"unsorted input lines detected",
	)));
	}

We'll want that check to be disabled if flamechart mode is on.

[jonhoo]

@That3Percent The latest commit should at least not fail with that error — care to try again?

[AnderEnder]

@jonhoo and @That3Percent,

I added a condition to frames. And result is produced for your example: flame.svg

[That3Percent]

I gave this a try and I'm really happy with the result. This is now much better than the flame graph that flame produces because the bars line up with the actual time within the method that an event occurred rather than shifting to fill any gaps. Great! This retains a lot of useful information.

Once this makes it into a release on crates.io I'll include it in firestorm and do a proper release of that with docs and the full treatment.

[jonhoo]

@That3Percent Excellent, glad to hear it! Should be ready for release in not too long.

@AnderEnder Could you include the provided input file and the produced output file as a test case? If you get stuck, @jasonrhansen may be able to give you some pointers too. Once we have that, I think this is good to land!

[jonhoo]

Oh, and an update to the CHANGELOG please!

[That3Percent]

@AnderEnder Attached is a new input file. there were some minor issues with the last one (when I was removing entries that had 0 time, it was possible to have adjacent stacks with the same name that were actually the same stack).

flames.txt

[AnderEnder]

@jonhoo, done. Should commit "make func_frameattrs atribute contidional" be removed from this PR?

[jonhoo]

Nope, all good, thanks!

[jonhoo]

Released in 0.10.0.