993775 - High CPU usage on a jsfiddle example

Status: NEW

(Core :: General, defect)

Description

[Tingan Ho]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36

Steps to reproduce:

Go to http://jsfiddle.net/hD6wr/
The CPU usage of Firefox is around 19%, which is super high. I have tried to use the 
GPU using translateZ(0).



Expected results:

In Safari which the performance is the best uses only 2-3% CPU on my Macbook Pro Intel Core i5.

Comment 1

[Nicholas Nethercote [inactive]]

I did some measurements with |mach power| on Mac.

Nightly:

>     total W = _pkg_ (cores + _gpu_ + other) + _ram_ W
> #01 15.71 W = 12.12 ( 0.41 +  4.64 +  7.07) +  3.59 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                 109    137.79                                      65.87   51.28             255.04
>   firefox                          41894  106.32    73.76  0.13    0.00               63.54   49.62             255.05
>   plugin-container                 41896  26.83     84.63  0.00    0.00               1.70    1.13              0.00
>   Terminal                         208    5.00      92.36  0.00    0.00               0.57    0.47              0.00
> com.apple.WindowServer             68     102.31                                      62.44   16.19             254.98
>   WindowServer                     141    102.70    71.91  1.93    0.17               62.44   16.19             254.99
> kernel_coalition                   1      19.82                                       217.72  193.89            0.00
>   kernel_task                      0      16.25     0.00   3.87    0.00               217.62  193.87            0.00

Safari:

>     total W = _pkg_ (cores + _gpu_ + other) + _ram_ W
> #01  7.01 W =  5.06 ( 0.14 +  0.52 +  4.39) +  1.95 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.WindowServer             68     78.09                                       120.66  92.40             59.13
>   WindowServer                     141    78.09     73.99  60.55   0.10               120.63  92.40             59.13
> kernel_coalition                   1      9.42                                        71.71   69.11             0.00
>   kernel_task                      0      6.68      0.00   0.00    0.00               71.61   69.01             0.00
> com.apple.Safari                   442    0.25                                        0.57    0.50              0.00
>   com.apple.WebKit.WebContent      41820  0.14      59.38  0.00    0.00               0.33    0.33              0.00
>   com.apple.WebKit.WebContent      41822  0.12      59.54  0.00    0.00               0.17    0.10              0.00
>   Safari                           41817  0.01      57.76  0.00    0.00               0.07    0.07              0.00

Chrome:

>     total W = _pkg_ (cores + _gpu_ + other) + _ram_ W
> #01 14.60 W = 11.37 ( 0.82 +  3.73 +  6.82) +  3.23 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                  443    393.05                                      237.28  175.13            196.60
>   Google Chrome Helper             41927  169.52    66.77  0.00    0.00               114.03  85.37             196.60
>   Google Chrome                    41923  119.35    71.80  0.40    0.27               63.51   46.72             0.00
>   Google Chrome Helper             41930  107.97    69.41  0.00    0.00               59.75   43.05             0.00
> com.apple.WindowServer             68     91.71                                       134.88  43.65             201.08              
>   WindowServer                     141    91.72     75.85  74.81   0.10               134.89  43.65             201.09              
> kernel_coalition                   1      21.94                                       181.23  89.43             0.00                
>   kernel_task                      0      18.61     0.00   2.10    0.00               181.07  89.37             0.00  

Nightly is a little worse than Chrome, which is much worse than Safari.

Comment 2

[Nicholas Nethercote [inactive]]

Those measurements are on the view where I see a menu on the LHS, and then four windows labelled "HTML", "CSS", "JavaScript" and "Result". In the "Result" window I see a Login screen with a pastel coloured background.

Comment 3

[Albert Scheiner [:alberts]]

I am seeing similar numbers as Tingan.