1055208 - Send fewer STARTUP_ histograms in Telemetry pings

Status: RESOLVED DUPLICATE of bug 1300491

(Toolkit :: Telemetry, defect)

Description

[:Irving Reid (No longer working on Firefox)]

We currently create duplicate histograms for some Telemetry probes at the end of browser start up. As part of trying to reduce overall Telemetry data size, we should tighten up the filters to only collect STARTUP_ histograms for data points that are useful.

http://hg.mozilla.org/mozilla-central/annotate/bf27e27c994d/toolkit/components/telemetry/TelemetryPing.jsm#l673

Comment 1

[Roberto Agostino Vitillo (:rvitillo)]

As noted by Irving on IRC, we already grep on SQLITE|HTTP|SPDY|CACHE|DNS. Vladan, who requested at the time to add those probes in the first place? Are you suggesting to add a new field to the probes in Histograms.json to discern if they should be accounted for also during startup or not?

Comment 2

[Vladan Djeric (:vladan)]

Attachment: tighterRegex.patch

(In reply to Roberto Agostino Vitillo (:rvitillo) from comment #1)
> As noted by Irving on IRC, we already grep on SQLITE|HTTP|SPDY|CACHE|DNS.
> Vladan, who requested at the time to add those probes in the first place?

Taras requested STARTUP_ histograms back in bug 701863. The intent was to determine if any of these components were responsible for very long startup times.
One of the fruits of this investigation was the discovery that Firefox often loads pages before it has even painted its UI. This was fixed in follow up bugs.

> Are you suggesting to add a new field to the probes in Histograms.json to
> discern if they should be accounted for also during startup or not?

No. I think this regex is a bit opaque & hacky but it's tolerable for now. We should take another look at the STARTUP_ histogram data though.

Also, the current regex includes too many histograms, it creates STARTUP_* clones of many histograms that are not relevant to startup delays, e.g. MEMORY_STORAGE_SQLITE, FONT_CACHE_HIT, HTTPCONNMGR_TOTAL_SPECULATIVE_CONN, etc

If we tighten up the regex a little bit, we can eliminate 49 potential STARTUP_ histograms out of the current 240.

Comment 3

[:Irving Reid (No longer working on Firefox)]

Comment on attachment 8483214 [details] [diff] [review]
tighterRegex.patch

Review of attachment 8483214 [details] [diff] [review]:
-----------------------------------------------------------------

::: toolkit/components/telemetry/TelemetryPing.jsm
@@ +237,5 @@
>    // duplicate submissions.
>    _uuid: generateUUID(),
>    // Regex that matches histograms we care about during startup.
>    // Keep this in sync with gen-histogram-bucket-ranges.py.
> +  _startupHistogramRegex: /^(MOZ_SQLITE_|HTTP_|SPDY_|CACHE_|DNS_)/,

Needs the corresponding change to toolkit/components/telemetry/gen-histogram-bucket-ranges.py (or, if they don't actually need to be kept in sync, the comment one line up needs to be removed).

We're still gathering a pile of data that we don't have a specific use for, but hopefully we'll expire a bunch of the underlying histograms.

Comment 4

[Chris H-C :chutten]

STARTUP_* probes were removed in bug 1300491