970927 - High power consumption on Forbes while idling, with CSS transition on 'transform' for an element inside of a "top: 3000px" subtree

Status: RESOLVED INCOMPLETE

(Core :: Layout, defect, P4)

Description

[Roberto Agostino Vitillo (:rvitillo)]

Attachment: Energy consumption on Linux.

Firefox is consuming an excessive amount of CPU resources while idling on Forbes.com compared to Chrome on Linux.

Comment 1

[Roberto Agostino Vitillo (:rvitillo)]

Attachment: Testcase 1

It seems that when a CSS animation is not visible (i.e. it's positioned outside of the viewport), Chrome does a better job at reducing the number of instructions executed. Both FF and Chrome have about 50-60 wakeups/sec on OSX but the latter does much less work per wakeup.

Comment 2

[Mats Palmgren (inactive)]

See bug 962594 comment 9 though.

Comment 3

[Daniel Holbert [:dholbert]]

I'm not sure we can easily optimize away any wakeups (refresh driver ticks) here, since the property being animated in those ticks ("transform") could be animated to a value (like "translatey(-3000px)") that would put the element in view.  And we can't find out whether it's got such a value without actually evaluating the animation (ticking).

Comment 4

[Daniel Holbert [:dholbert]]

[Note that the dependency on bug 962594 may end up being weak; in that bug, the animated content is "display:none" and hence much easier to prove non-visible/non-layout-impacting, as compared to the abspos content  in this bug's testcase.

However, I suppose it's likely that bug 962594 will be fixed before this bug is, since it's more straightforward; and if we can come up with a fix here, it's feasible that it might share some of the mechanics. So maybe the dependency makes sense.]

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

We'll do a lot less work on animations of transforms once we have OMT Animations turned on on platforms other than B2G.  Other than that I'm not sure what to do about this.

Comment 6

[Nicholas Nethercote [inactive]]

I took measurements of the attached test with |mach power| on Mac.

Nightly:

>     total W = _pkg_ (cores + _gpu_ + other) + _ram_ W
> #01  5.12 W =  3.75 ( 0.59 +  0.00 +  3.16) +  1.37 W
>
> 1 sample taken over a period of 30.000 seconds
>
> Name                               ID     CPU ms/s  User%  Deadlines (<2 ms, 2-5 ms)  Wakeups (Intr, Pkg idle)  GPU ms/s
> com.apple.Terminal                 239    269.99                                      78.94   67.28             0.00    
>   plugin-container                 33665  194.72    93.66  2.40    2.07               9.93    7.60              0.00    
>   firefox                          33664  70.80     74.92  6.53    0.10               68.61   59.41             0.00    
>   Terminal                         446    5.24      92.59  0.00    0.00               0.37    0.27              0.00    
> kernel_coalition                   1      11.43                                       44.62   28.29             0.00    
>   kernel_task                      0      8.95      0.00   4.20    0.03               44.52   28.22             0.00 
> com.apple.WindowServer             69     0.66                                        0.30    0.27              0.48    
>   WindowServer                     144    0.66      23.58  0.07    0.07               0.30    0.27              0.48    

Chrome:

>     total W = _pkg_ (cores + _gpu_ + other) + _ram_ W
> #01  3.50 W =  2.19 ( 0.09 +  0.02 +  2.08) +  1.31 W
>
> 1 sample taken over a period of 30.000 seconds
>
> Name                               ID     CPU ms/s  User%  Deadlines (<2 ms, 2-5 ms)  Wakeups (Intr, Pkg idle)  GPU ms/s
> com.google.Chrome                  354    34.52                                       52.58   43.55             0.28    
>   Google Chrome Helper             33699  33.51     63.23  1.30    0.00               51.02   42.72             0.00
>   Google Chrome Helper             33693  0.81      47.19  0.00    0.00               0.20    0.20              0.28    
>   Google Chrome                    33688  0.69      61.85  0.30    0.00               1.37    0.63              0.00    
> kernel_coalition                   1      14.15                                       48.58   41.35             0.00    
>   kernel_task                      0      11.71     0.00   4.70    0.00               48.49   41.25             0.00    
> com.apple.WindowServer             69     1.60                                        0.70    0.63              1.64    
>   WindowServer                     144    1.60      41.00  0.10    0.03               0.70    0.63              1.64

Safari failed to load the test.

So we're a bit worse than Chrome, but not a lot, and 5 W is not that far from the floor of 3.5 W on my laptop.

Comment 7

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Daniel, given that this bug is around 8 to 9 years old I would suggest to close it as incomplete. What do you think?

Comment 8

[Daniel Holbert [:dholbert]]

Yeah. I'm not seeing a substantial perf difference (in terms of top usage) between Firefox and Chrome (or particularly high CPU usage from Firefox) here. Let's close as incomplete for now.