1013011 - DMD: Remove stack frame records

Status: RESOLVED FIXED

(Core :: DMD, defect)

Description

[Nicholas Nethercote [inactive]]

DMD's most useful output is stack trace records -- all the allocations with identical stacks get aggregated into a single record. This is useful, and easy to understand.

But sometimes you have lots of stacks that are conceptually the same but have very small variations. In an attempt to identify cases like these, I added stack frame records. A stack frame record is a merging of every stack trace record that had an allocation stack trace containing its stack frame.

It was a reasonable idea, but in practice it's not useful. It's hard to understand and is dominated by functions like XRE_main() and NS_ProcessNextEvent(). I've barely used it and I doubt anyone else has.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: DMD: Remove stack frame records

Eric: other than me, you've looked at DMD as much as anyone has lately, so you
might as well review this.

Once it lands, I'll update the wiki page accordingly.

Comment 2

[Andrew McCreight [:mccr8]]

I've found it sort of useful before on some of my B2G skulking expeditions, but it feels like something that could easily be done in a post-processing step.  I feel like it also ended up being a huge percentage of the total log, which make look around more annoying.

Comment 3

[Nicholas Nethercote [inactive]]

> it feels like something that could easily be done in a post-processing
> step.

Good point. A few dozen lines of Python could replicate a few hundred lines of C++.

Comment 4

[Eric Rahm [:erahm]]

Comment on attachment 8425168 [details] [diff] [review]
DMD: Remove stack frame records

Review of attachment 8425168 [details] [diff] [review]:
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lgtm. I agree, if we need this functionality post processing is probably a better place. r=me

Comment 5

[Nicholas Nethercote [inactive]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/170de1040e9a

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/170de1040e9a