Tested on Mac 10.11.6 using chrome stable M54 # 54.0.2840.71 and did not observe any issue in the document interface.

Attached screencast for reference.

@bl.nero -- could you please try a system restart and try again with a fresh profile without any extensions and if you still face the issue please write us your observations. If possible provide us a screencast of the issue.

Thanks !

Deleted: 660068.mp4 18.0 MB

660068.mp4 18.0 MB Download

I am also unable to reproduce the issue. An easy way to test with a clean profile is to download Google Chrome Canary, and to try out the webpage there. 

I've captured screencasts. I can't upload them here, since they are too large; here are links to Drive:

https://drive.google.com/file/d/0B7zZHcodUke2YnRRRk1iTFdCMEU/view?usp=sharing
https://drive.google.com/file/d/0B7zZHcodUke2LWw5ME5KUUR2V0E/view?usp=sharing

The first one shows the behavior in Chrome. As you can clearly see, it's laggy as hell. The second one shows the same thing in Firefox. Although it may not have had the best day in terms of typing, it still runs circles around Chrome, and in case of scrolling it's even more visible.

Details: I've performed experiments using a brand new Chrome profile with all extensions disabled. Only one browser was running at any given time. The computer was freshly restarted to a clean state (no other significant apps running apart from the QuickTime recorder). My hardware: MacBook Pro (Retina, 13-inch, Early 2015), 2,7 GHz Intel Core i5, 16 GB 1867 MHz DDR3, Intel Iris Graphics 6100 1536 MB.

I've also conducted a separate experiment (to avoid performance impact) and gathered timeline data from Chrome dev tools, but since it's really huge (over 300MB), I won't upload it immediately unless you guys think that it would help you.

(I'm sorry, I messed up the links: the FIRST one is FF, and the SECOND one is Chrome.)

I tried just holding down the down arrow - the scrolling got slower and slower the further I got into the document. When I released the key and held it down again the scrolling was just as slow as when I stopped (I thought maybe Chrome was getting bogged down from not having a chance to clean up resources). There must be some calculation occurring on each key event that's dependent on how far down into the document you are (like number of characters).

With QuartzDebug I saw excess redraws of the account name and a column along the left side of the document's edge - those are Google Docs issues. There might be some Blink issues as well, but a big issue I saw in Chrome Mac was excessive redraws of the omnibox, each extension icon, and the entire tab strip. Tons of flickering in QuartDebug with the key held down.

erikchen@ - can you look into what's triggering all the redrawing in the top chrome?
 

bl.nero@ Could you record a trace for us?

1. Go to about:tracing
2. Click "Record" in the top left.
3. Click "Javascript and Rendering"
4. Click "Record" button in the dialog.
5. Switch tabs and perform the actions in the google doc showing it being slow.
6. Go back to about:tracing and click "Stop".
7. Click "Save" in the top left.
8. Attach the trace here.

I know it's a bit annoying to do it, but it contains a bunch of helpful information to debug this issue. :)

Attaching the trace. Thanks for investigating!

Deleted: trace_docs-perf-trace.json.gz 6.9 MB

trace_docs-perf-trace.json.gz 6.9 MB Download

Minor note: the trace above was captured using the same clean profile as the screencasts, but the machine was running many other processes (a couple of servers, other browser profiles, and one docker image). I made sure, however, that the CPU and RAM utilization is sane before I started tracing. If you need a trace from a more "sterile" environment, please let me know, because I'll need to do it over the weekend.

Any update on this issue? As of now (Chrome version 58.0.3029.110), this is still visible.

erikchen@ - is this a Chrome problem or a Docs problem?

Friendly ping.

Aaaaaaand another ping.

Now Firefox is also impaired, only in a different way: the cursor stops for half a second when scrolling through an empty paragraph. The toolbar buttons are blinking at that time. This particular problem doesn't occur on Chrome. May be something separate, probably Docs-specific, but honestly, I don't know, and I don't want to waste time for more profiling.

I'm a little disappointed here. The issue is clearly reproducible, as shrike@ confirmed. It's been there for at least a year. However, it looks like people who do serious editing on large documents are just not the target group here. Regardless of whether it's a Docs or Chrome issue, it's sad that functionality of this combo is limited to writing documents that span no longer than a couple of pages.

I took a look at the trace. It looks like the Docs renderer gets backed up with painting/redrawing. 

Also not sure if Docs or Chrome bug. Over to GPU triage to take a look.

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	Screen Shot 2017-12-12 at 9.31.22 AM.png 98.6 KB View Download

Handing off to blink-paint since the trace seems to involve blink paint (and layout)

We're getting hammered with layer updates, which is typical now in Google Docs due to the large numbers of layers created for text.

Sorry for continuing discussion on a closed issue, but the one that is referenced as duplicate is confidential, and I can't access it: I tried to reproduce this issue on a Windows laptop, and I was able to reproduce it at the first attempt. This is an Intel Core i5 machine with 16GB of RAM, and after I scroll through the document and press a letter key, the updates come in batches roughly every second or so. This is really, really bad.

If it's not a Chromium bug, can someone make me a favor and somehow escalate it to the Docs team? I recently decided to revisit this topic, because I wanted to buy a Chromebook, but then I realized that ironically, by buying Chromebook I would need to switch From Google Docs to MS Office. (Yes, that's how it looks.)