1171226 - Reading heap snapshots is *really* slow

Status: RESOLVED FIXED

(DevTools :: Memory, defect)

Description

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: Screenshot of Instruments profile

Almost all time spent de-duplicating type names when creating DeserializedNodes.

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: WIP: Stop de-duplicating strings

Comment 2

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

(In reply to Nick Fitzgerald [:fitzgen][:nf] from comment #1)
> Created attachment 8614964 [details] [diff] [review]
> WIP: Stop de-duplicating strings

Reading a heap snapshot of the full process is basically a perma-beachball without this patch. With this patch, it is only ~1500 ms.

There is something funky going on in the de-duping, resulting in quadratic behavior or some such, because it shouldn't take minutes long.

Comment 3

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: WIP Fix UniqueStringHashPolicy::match

Comment 4

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: Fix mozilla::devtools::UniqueStringHashPolicy::match for strings with the same prefix

Comment 5

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Comment on attachment 8614994 [details] [diff] [review]
Fix mozilla::devtools::UniqueStringHashPolicy::match for strings with the same prefix

Note: I ensured that the new test fails without the change.

Comment 6

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=5f2fdcefa7db

Comment 7

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/26d5497b19e9

Comment 8

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/26d5497b19e9