1341882 - Slow performance at drawing rectangles on Google Slides

Status: NEW

(Core :: Graphics, defect, P3)

Description

[(no longer active)]

See this profile: https://perfht.ml/2l12Pzj

Here is what I did: I loaded <https://docs.google.com/presentation/d/1gqQpeG1vHky4nZ45mIYSC5DAEFX-5HipjemLwhBDe1c/edit?pli=1> in a tab (needs LDAP login) and waited for it to be fully loaded, and then after a while I clicked on the thumbnail for slide 5.

We spend ~450ms in SkScan::AntiFillRect.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

This is interesting. The operation should be quite fast (some approximation of memset). Maybe it's doing it a large freshly allocated buffer?

I wasn't able to reproduce the problem when trying to profile in instruments.

Comment 2

[Markus Stange [:mstange]]

I cannot reproduce it either.

In your profile it's drawing a background color display item, which is probably the first item to draw to that part of the memory. So it could be drawing to a fresh tile and waiting to page in (or zero-fill-on-demand) that piece of memory.

Comment 3

[(no longer active)]

I tried to reproduce again on the document that I have left open since yesterday: https://perfht.ml/2mbPwBc  Only 76ms here.

Another time, immediately after a reload: https://perfht.ml/2mbPQQq  Only 56ms here.

Could there be a bug which only causes this to take a long time in some cases?

Comment 4

[Markus Stange [:mstange]]

IIRC our tile pool starts discarding tiles after a time, and if you encounter a page that has more or bigger layers and needs to allocate new tiles, you're more likely to hit this bug.

Comment 5

[(no longer active)]

(In reply to Markus Stange [:mstange] from comment #4)
> IIRC our tile pool starts discarding tiles after a time, and if you
> encounter a page that has more or bigger layers and needs to allocate new
> tiles, you're more likely to hit this bug.

Markus, is there more investigation needed here?

Comment 6

[Markus Stange [:mstange]]

Maybe, but I think whoever looks at the tile pool next should focus their attention on bugs like bug 1346365 first.