bazelbuild/bazel

place "Garbage Collector" profile track near system stats

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#29310 opened on Apr 15, 2026

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 (2 comments) (0 reactions) (0 assignees)Java (25,384 stars) (4,465 forks)batch import
P4help wantedteam-Remote-Exectype: feature request

Description

The "Garbage Collector" profile track is sorted to the top of the perfetto UI by https://github.com/bazelbuild/bazel/blob/ee72e6ddbcf19db6e4ddf127bde56ca5676de780/src/main/java/com/google/devtools/build/lib/profiler/ThreadMetadata.java#L89. In paticular, it's often useful to examine the GC track in conjunction with the memory tracks. While it's possible to reorganize the tracks in the Perfetto UI, I propose to move the GC track down by the rest of the system stats by default.

Contributor guide

Tech stack
java
Domain
performanceobservability
Issue type
feature
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.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
85
Research direction
The issue proposes moving the 'Garbage Collector' profile track in the Perfetto UI to be near system stats. The relevant code is in ThreadMetadata.java at line 89, where the track sort order is set. Examine that file to understand the current sorting mechanism and determine how to change the order of the GC track. Check the issue comments for any additional context or suggested approach.