firefox-devtools/profiler

Repeated invocations of processThreadCPUDelta during symbolication take up more time than necessary

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#3,481 opened on Aug 5, 2021

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help wantedperfprofile data

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Description

Profile: https://share.firefox.dev/2X0vayw

Every time symbolication updates the thread, processThreadCPUDelta is called again for the modified profile. It seems like this is something that could be done only once. We could bake the guarantees that processThreadCPUDelta makes into the processed profile format. That means, instead of calling it from a selector, we would call it in these two places:

  • During profile processing, and
  • In an upgrader for the processed profile format.

It's not taking a ton of time, and symbolication is slow already, but it's one of many things that adds up to the slowness and it might be easy to fix.

┆Issue is synchronized with this Jira Task

Contributor guide

Research direction
Identify the calls to processThreadCPUDelta in the symbolication workflow, then refactor to call it only during profile processing and in an upgrader for the processed profile format, as suggested in the issue.
Tech stack
typescript
Domain
performance
Issue type
Performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitTypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65