1219878 - [Metrics] There is no histogram definition for uss memory ('enhanced' metrics)

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Metrics, defect)

Description

[Russ Nicoletti [:russn]]

When the metrics level is "Enhanced" and 'Unique Set Size' is selected on the Developer HUD settings page, the "advanced telemetry" system will attempt to collect "uss" memory metrics. However, there is no histogram corresponding to uss memory and as a result no uss memory metrics will be collected and the following errors will appear in the logcat:

E/GeckoConsole( 1780): Content JS ERROR: Histogram error is metricname added to histograms.json:DEVTOOLS_HUD_USS

When the uss memory histogram is defined, output like the following should appear in the logcat:

"DEVTOOLS_HUD_USS":{"callscreen":{"min":20000000,"max":100000000,"histogram_type":1,"sum":1930792960,"sum_squares_lo":3003121664,"sum_squares_hi":29934735,"ranges":[0,20000000,24444444,28888889,33333333,37777778,42222222,46666667,51111111,55555556,60000000,64444444,68888889,73333333,77777778,82222222,86666667,91111111,95555556,100000000],"counts":[0,0,0,0,0,0,0,0,0,0,0,29,0,0,0,0,0,0,0,0]},"keyboard":{"min":20000000,"max":100000000,"histogram_type":1,"sum":448352256,"sum_squares_lo":3841982464,"sum_squares_hi":1623130,"ranges":[0,20000000,24444444,28888889,33333333,37777778,42222222,46666667,51111111,55555556,60000000,64444444,68888889,73333333,77777778,82222222,86666667,91111111,95555556,100000000],"counts":[29,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}

Comment 1

[Russ Nicoletti [:russn]]

Attachment: uss_hist.patch

I'm finding that 'system' and 'callscreen' use about 90MB of uss memory. So I set the 'high' value for the uss histogram at 100MB. In order to provide reasonable granularity for the apps that only use 20-40MB, I've specified 50 buckets (2MB per bucket).

Comment 2

[Vladan Djeric (:vladan)]

Comment on attachment 8680808 [details] [diff] [review]
uss_hist.patch

Review of attachment 8680808 [details] [diff] [review]:
-----------------------------------------------------------------

::: toolkit/components/telemetry/Histograms.json
@@ +9176,5 @@
> +    "alert_emails": ["[e-mail]","[e-mail]"],
> +    "expires_in_version": "52",
> +    "kind": "linear",
> +    "keyed": "true",
> +    "description": "The USS memory consumed by an application, keyed by appName.",

nit: usually the description is the last field

Comment 3

[Vladan Djeric (:vladan)]

Comment on attachment 8680808 [details] [diff] [review]
uss_hist.patch

Review of attachment 8680808 [details] [diff] [review]:
-----------------------------------------------------------------

::: toolkit/components/telemetry/Histograms.json
@@ +9179,5 @@
> +    "keyed": "true",
> +    "description": "The USS memory consumed by an application, keyed by appName.",
> +    "low": "20000000",
> +    "high": "100000000",
> +    "n_buckets": 50

FYI, this is what the bucketing for this histogram looks like with n_buckets=50
https://telemetry.mozilla.org/histogram-simulator/#low=20000000&high=100000000&n_buckets=50&kind=linear&generate=normal

This is what it looks like with n_buckets=52 and high=120M (each bucket becomes exactly 2MB wide)
https://telemetry.mozilla.org/histogram-simulator/#low=20000000&high=120000000&n_buckets=52&kind=linear&generate=normal

Comment 4

[Russ Nicoletti [:russn]]

Attachment: addressed comments 2 and 3

Thanks, vladan. I have updated the patch to address comments 2 and 3.

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/b2g-inbound/rev/01b7c7949604

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/01b7c7949604

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/releases/mozilla-b2g44_v2_5/rev/01b7c7949604

Comment 8

[Carsten Book [:Tomcat]]

removing the b2g 2.5 flag since this commit has been reverted due to an incorrect merge, sorry for the confusion