1478953 - style.foo = bar changes are slow

Status: NEW

(Core :: CSS Parsing and Computation, enhancement, P3)

Description

[Olli Pettay [:smaug][[e-mail]]]

A testcase I've used for profiling is
https://bugzilla.mozilla.org/attachment.cgi?id=8983177
"withoutmutationobserver" part is perhaps the most valid part for this bug.

this is with
export RUSTC_OPT_LEVEL=2

Mostly stylo but also some DOM attribute handling

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

https://perfht.ml/2LTXLuT is better link

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Color is a bit more annoying than the rest of the properties... But yeah, there are improvements that could be made there.

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

Attachment: style.top

Another test.

On Linux 35% slower than Chrome.

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

https://perfht.ml/2MITpLD  is from MotionMark.

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

So parsing stuff and attribute setting is 5-10% of MotionMark.
This should probably be qf:p1.

Comment 7

[Daniel Holbert [:dholbert] (PTO until 2/24)]

smaug and/or emilio: from a [qf] categorization perspective, do you know whether this bug's use cases fall into pageload vs. responsiveness? (Or something else?)

(Intuitively it seems like "style.foo = bar" is primarily an after-page-load scenario, in response to interaction, though of course it could also be performed in an onload handler.)

Comment 8

[Olli Pettay [:smaug][[e-mail]]]

I haven't seen this badly during pageload.

Comment 9

[Olli Pettay [:smaug][[e-mail]]]

https://perfht.ml/2TS0BUD

I guess stylo should do something faster. set_property looks particularly hot.