603831 - google fishtank demo suddenly slow with 1000 fishies

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Christopher Blizzard (:blizzard)]

I'm using a somewhat old Macbook Pro with Windows 7 on it:

  Graphics

        Adapter Description
        NVIDIA GeForce 8600M GT

        Vendor ID
        10de

        Device ID
        0407

        Adapter RAM
        512

        Adapter Drivers
        nvd3dum nvwgf2um,nvwgf2um

        Driver Version
        8.16.11.8861

        Driver Date
        1-5-2010

        Direct2D Enabled
        true

        DirectWrite Enabled
        true

      GPU Accelerated Windows
      1/1 Direct3D 9

Playing the fish demo from google I get excellent smooth performance up to 500 fish.  When I go to 1000 fish there's some kind of cliff and the performance is very very choppy, like the GC is running all the time.

Comment 1

[Mike Shaver (:shaver emeritus)]

Lots of things could make us very choppy (like taking longer than frame-time to calculate and render a frame!) -- a quick poke with xperf will tell you what DLL we're in, and since windows has JS split out right now, that'll be a good hint.

Comment 2

[David Mandelin [:dmandelin]]

On my new box, it is 27-30 fps no matter how many fish I have (from 1 to 1000). I xperf'd it and got (as fractions of weight in Fx):

  mozjs.dll      9%
  xul.dll       12%
  ngoglv32.dll  68%

Sending over to gfx for now, although because the machines are so different we can't say for sure without getting a pair of xperf runs on your machine.

Comment 3

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

This is going to be heavily dependent on your window size, due to the readback disaster that's still going on.  So if you have a fullscreen Firefox window, you're almost certainly going to be limited by this.  If you make the window tiny (like 100x100 content area or so, just enough for the UI strip), the readback cost is greatly reduced -- I tend to go from highs in the 70's to highs in the 50's when going from 1 -> 1000 fishes with a small window.

Comment 4

[Joe Drew (not getting mail)]

We're now not reading back, and significantly faster. We still have GC pauses, obviously, but 1000 fishies is plenty fast on my MacBook now.