833629 - Rebucket memory telemetry

Status: RESOLVED FIXED

(Toolkit :: Telemetry, defect)

Description

[Justin Lebar (not reading bugmail)]

1GB is the largest RSS bucket, and about 13% of users have RSS over 1GB.  We have a similar but less acute problem with explicit and the other memory reporters.

I don't suggest this lightly (because it messes up our ability to compare current performance to the past), but I think we need to rebucket these histograms.

Comment 1

[Nathan Froyd [:froydnj]]

I assume you want to rebucket because you want that single 1GB+ bucket to be more fine-grained?

What do you see as the benefit of this finer bucketing?  (And ancillary effects on smaller buckets.)

Comment 2

[Justin Lebar (not reading bugmail)]

> What do you see as the benefit of this finer bucketing?

If we make a change which takes someone from using 2gb to 1.1gb of RAM (or vice versa!), it won't show up in telemetry.

> (And ancillary effects on smaller buckets.)

I'm planning to add many more buckets at the same time, so we'll get more insight into the smaller buckets, not less.

Comment 3

[Justin Lebar (not reading bugmail)]

Attachment: Patch, v1

I went through each of the memory-related histograms.  For those with a significant number hitting the right edge of the histogram, I made the histogram much wider (to 16GB) and much higher resolution (200 buckets).  Hopefully this will keep us from having to rebucket again.

Comment 4

[Justin Lebar (not reading bugmail)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/d800ecb735c9

Thanks for the quick review!

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/d800ecb735c9