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Document object names flag for dev tools heap snapshots

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Names for Blink internal objects are helpful to have when debugging
certain leak or OOM scenarios, but the steps to enable them aren't
written down anywhere I could find. Document them for future reference.

Change-Id: Ibe4092cdd255b962dea45f3c841d48b4799f5702
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5032492
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Kevin Babbitt <kbabbitt@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1225537}
This commit is contained in:
Kevin Babbitt
2023-11-16 16:41:40 +00:00
committed by Chromium LUCI CQ
parent 411f33dae7
commit dfa8c8cfb3
1 changed files with 22 additions and 1 deletions

23
docs/memory/tools.md

@ -16,7 +16,7 @@ Here is a table of common area of inquiry and suggested tools for examining them
|----------------------- | ------- |
| Which subsystems consuming memory per process. | [Global Memory Dumps](#global-memory-dumps), [Taking memory-infra trace](#memory-infra-trace) |
| Tracking C++ object allocation over time | [`diff_heap_profiler.py`](#diff-heap-profiler), [Heap Details in chrome://tracing](#heap-dumps-chrome-tracing) |
| Suspected DOM leaks in the Renderer | [Real World Leak Detector](#real-world-leak-detector) |
| Suspected DOM leaks in the Renderer | [Developer Tools Heap Snapshots](#dev-tools-heap-snapshots), [Real World Leak Detector](#real-world-leak-detector) |
| Kernel/Driver Memory and Resource Usage | [perfmon (win), ETW](#os-tools) |
| Blackbox examination of process memory | [VMMAP (win)](#os-tools) | Understanding fragmentation of the memory space |
| Symbolized Heap Dump data | [Heap Dumps](#heap-dumps) | Grabs raw data for analysis by other tools |
@ -219,6 +219,27 @@ analyze it.
TODO(ajwong): Add screenshot or at least reference the more detailed
memory-infra docs.
-----------
## <a name="dev-tools-heap-snapshots"></a> Developer Tools Heap Snapshots
Heap snapshots provide views of objects on the Oilpan and V8 heaps and retainer
relationships between them. General documentation is here:
https://developer.chrome.com/docs/devtools/memory-problems/heap-snapshots/
By default, many objects on the Oilpan heap will be labeled as "InternalNode".
To capture detailed symbol names for them, follow these steps:
1. Add the following to gn args and rebuild: `cppgc_enable_object_names = true` <br/>
Or use [Chrome for Testing](https://googlechromelabs.github.io/chrome-for-testing/) prebuilt binaries; they have this flag enabled.
2. In Developer Tools, under Settings | Experiments, check "Show option to
expose internals in heap snapshots"
3. Reload Developer Tools (there will be a button for this at the top of the
window)
4. On the Memory pane, under Select profiling type | Heap snapshot, check
"Expose internals (includes additional implementation-specific details)"
-----------
## <a name="real-world-leak-detector"></a> Real World Leak Detector (Blink-only)