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Issue 733032 link

Starred by 3 users

Issue metadata

Status: WontFix
Owner: ----
Closed: Jun 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 3
Type: Bug



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Loading large text files is unreasonably slow

Project Member Reported by scottmg@chromium.org, Jun 14 2017

Issue description

1. Open https://gist.githubusercontent.com/sgraham/5a550d6465c8f06891de45fd6bf9b4f9/raw/8e67979d5c563c05ad73e1bb01a0b6dc536f5e46/gistfile1.txt

2. Attempt to scroll to the bottom to see an error.

In Chrome Stable (Version 58.0.3029.110 (64-bit)) on a 2014 MacBook Pro, this takes ~1.5 minutes with the cpu spinning at 100% to become interactive.

By contrast on the same hardware in Safari "Version 10.1.1 (12603.2.4)" it takes ~5 seconds and is reasonably responsive right away.

Not sure where the time is going yet. Maybe caching things for the gpu?
 
(Realized I was behind on Stable, but I don't notice any difference on 59.0.3071.86).
Components: -Blink Blink>Loader
I can reproduce on Chrome 59 only sometimes (e.g. the first time it loads).
Afterwards, performance is similar to the reported timings for Safari.
Maybe something with loading?

Comment 3 by tzik@chromium.org, Jun 20 2017

Components: -Blink>Loader Blink>Layout
The main thread is blocked mostly by a layout task.

Comment 4 by e...@chromium.org, Jun 20 2017

Status: WontFix (was: Untriaged)
Large text documents with long lines without white-space is the worst case scenario for our line breaking implementation which accounts for 95% of the layout time in this case. This is a known problem and something we are working on.

Once we enable LayoutNG for inlines by default this should improve dramatically.
Tracked in issue 636993.

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