#12675 BLOC 13.2.0: Zooming in Browse decreases perfomance

[Zarro Boogs per Child]

#12675: Zooming in Browse decreases perfomance
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           Reporter:  reuben        |       Owner:  dsd          
               Type:  defect        |      Status:  new          
           Priority:  blocker       |   Milestone:  13.2.0       
          Component:  not assigned  |     Version:  not specified
         Resolution:                |    Keywords:               
        Next_action:  never set     |    Verified:  0            
Deployment_affected:                |   Blockedby:               
           Blocking:                |  
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Comment(by dsd):

 This can be reproduced on 13.2.0 build 5 for XO-1.75 and XO-4 as well.

 It also reproduces on 12.1.0 on XO-1.75, i.e. it is not a new issue.

 Switching to fbdev makes no obvious difference, the system still struggles
 along while the zoomed-in webpage is on the screen, presumably due to the
 constant animations on that page.

 Using perf on XO4 shows that pixman is the biggest CPU eater here.
 Catching the hot function in gdb shows that it is called in the composite
 path, i.e. the graphics driver is rejecting some composite operation in
 CheckComposite so it falls back to software rendering. pixman's neon
 codepaths are hit but don't appear to make this much smoother than on
 XO-1.75.

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Ticket URL: <http://dev.laptop.org/ticket/12675#comment:3>
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