1579876 - Add telemetry to measure ratio of parsing versus streaming.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P2)

Description

[Nicolas B. Pierron [:nbp]]

This bug is a follow-up of Bug 1573904, which measured the streaming speed (= ss).

We attempt to measure the parsing time (= pt) and the streaming time (= st). However, we want to associate the streaming time with the parsing time, such that we do not have to guess this information later on.

The idea is to measure the following formulae:

x = (pt - st) / (pt + st)

This formulae should directly tells us whether the parsing time is larger (> 0) than the streaming time. Also, it is interesting telemetry wise, as it is bounded by -1 and 1.

Then, from this formulae, we can compute the following ratios:

st / pt = (1 - x) / (1 + x)

This also happens to be almost what we are interested in, modulo the missing parsing time, to compute the formulae mentioned in Bug 1573904, where we want:

Estimated time ≃ Min(pt * (1 - st / pt), 0) [knowing that the ratio of streamed bytes is roughly 100%]

Also, we can deduce the parsing speed (= ps) knowing the streaming speed (= ss) collected in Bug 1573904, as

ps = ss * (st / pt) [knowing that ps = b / pt ; ss = b / st]

Comment 1

[Nicolas B. Pierron [:nbp]]

Attachment: Data Review Request

Comment 2

[Nicolas B. Pierron [:nbp]]

Attachment: Bug 1579876 - Add telemetry to estimate the benefit of a streaming parser for JS. data-review=mlopatka

Comment 3

[Chris H-C :chutten]

Comment on attachment 9092072 [details]
Data Review Request

Load-balance to Martin.

Comment 4

[mlopatka]

Comment on attachment 9092072 [details]
Data Review Request

Data Steward review:

Thank you for submitting a review request. Everything looks good to me with the exception of the specified data collection duration. Please provide a public bug indicating termination efforts for this collection. I understand from the responses to data review form that this is a temporary data collection effort and has a planned end date.

> "I want this data to be collected for a few months with probably no need to extend the collection period.“

A public bug (with appropriate dependencies) should be filed, demonstrating that resourcing for backing out these probes is in place and the new probes are not intended for release uplift.

For future data review requests please note these (very minor) stylistic nits:
1- A little bit more verbosity in the response to  “What questions will you answer with this data?” Please feel free to pull more content from the bug itself into this field to facilitate review.
2- Please specify data category numbers in “List all proposed measurements and indicate the category of data collection for each measurement, using the Firefox data collection categories on the Mozilla wiki.“ For example: Category 1 “Technical data”

Comment 5

[Nicolas B. Pierron [:nbp]]

(In reply to mlopatka from comment #4)

Comment on attachment 9092072 [details]
Data Review Request

Data Steward review:

Thank you for submitting a review request. Everything looks good to me with
the exception of the specified data collection duration. Please provide a
public bug indicating termination efforts for this collection. I understand
from the responses to data review form that this is a temporary data
collection effort and has a planned end date.

"I want this data to be collected for a few months with probably no need to extend the collection period.“

A public bug (with appropriate dependencies) should be filed, demonstrating
that resourcing for backing out these probes is in place and the new probes
are not intended for release uplift.

Telemetry probes are set to expire by Firefox 75, and Bug 1580732 is filed to remove these telemetry probes.

For future data review requests please note these (very minor) stylistic
nits:
1- A little bit more verbosity in the response to “What questions will you
answer with this data?” Please feel free to pull more content from the bug
itself into this field to facilitate review.
2- Please specify data category numbers in “List all proposed measurements
and indicate the category of data collection for each measurement, using the
Firefox data collection categories on the Mozilla wiki.“ For example:
Category 1 “Technical data”

I thought I did explicit it in the data review request, probably missed due to the lack of formatting: (updated with the new tracking bug)

Measurement Description	Data Collection Category	Tracking Bug #
Percent of stream-time over stream + parse + bytecode time	Technical Data	Bug 1580732
Percent of parse-time over stream + parse + bytecode time	Technical Data	Bug 1580732
Percent of emit-bytecode-time over stream + parse + bytecode time	Technical Data	Bug 1580732
Percent of script which are streamed	Technical Data	Bug 1580732

Comment 6

[mlopatka]

Comment on attachment 9092072 [details]
Data Review Request

Data review r+

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/cf370574ac67
Add telemetry to estimate the benefit of a streaming parser for JS.  data-review=mlopatka r=jorendorff

Comment 8

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/cf370574ac67