[webkit-dev] LayoutTests results fallback graph

[Adam Barth]

On Sun, Jul 10, 2011 at 12:01 PM, James Robinson <jamesr at google.com> wrote:
> On Jul 10, 2011 10:53 AM, "Adam Barth" <abarth at webkit.org> wrote:
>> Hi webkit-dev,
>>
>> In trying to understand how our LayoutTest results system works, I've
>> created a digram of the fallback graph among the various
>> platform-specific directories:
>> https://docs.google.com/drawings/d/1z65SKkWrD4Slm6jobIphHwwRADyUtjOAxwGBVKBY8Kc/edit?hl=en_US
>>
>> Unfortunately, the fallback graph is not a tree, as one might imagine
>> initially.  I'd like to propose two small changes, which will
>> hopefully make the system more sensible globally.  I'm happy to do all
>> the work required to make these changes:
>>
>> 1) The "win" port should fall back either to "all" (the platform
>> independent results) or to "mac," but not to "mac-snowleopard", as it
>> does currently.  (I slightly prefer "all", but "mac" would also be
>> fine with me.)
>>
>> 2) The "chromium" port should fall back directly to "all" rather than
>> taking a detour through various Apple-maintained ports, as it does
>> currently.
>>
>> These changes have the following virtues:
>>
>> A) The resulting fallback graph will be a tree, making the fallback
>> graph easier to understand for both humans and automated tools.
>> B) The Chromium port will behave more like the other ports (e.g., GTK
>> and Qt), rather than being a parasite on Apple-maintained ports.
>>
>> These changes might increase the number of image baselines we store in
>> the tree for "chromium-mac"-derived ports (because there will be fewer
>> redundant fallback paths), but I expect that cost to be relatively
>> small because essentially every port has different image baselines
>> anyway
>
> Could you measure this? I suspect that not falling back on the mac pixel
> results will mean checking in a few thousand more pngs, but that's just a
> guess.

That seems possible:

abarth at quadzen:~/git/webkit/LayoutTests/platform/chromium-mac$ find .
-name "*.png" | wc -l
     900
abarth at quadzen:~/git/webkit/LayoutTests/platform/mac$ find . -name
"*.png" | wc -l
    6688
abarth at quadzen:~/git/webkit/LayoutTests/platform/chromium-win$ find .
-name "*.png" | wc -l
    5988
abarth at quadzen:~/git/webkit/LayoutTests/platform/chromium-linux$ find
. -name "*.png" | wc -l
    5731

However, I would expect those savings to disappear once we finish
moving chromium-mac to Skia.

Adam