[webkit-dev] Parallel image decoders are up for review

[KwangYul Seo]

Thank you letting me know this information!

On Tue, Jul 17, 2012 at 5:41 AM, Alpha Lam <hclam at chromium.org> wrote:

> Hi!
>
> This is great work!
>
There's work in the Chromium port going on that has a similar goal as your
> parallel image decoding effort. There are some parts that we overlap that I
> think should be discussed to avoid clashes.
>
>
What's  the current progress of Chromium work? Can I check out the source
code? Do you have a design document?

Here's some background information of what we're doing. In Chromium port
> there's a deferred painting mode that we record painting commands and
> playback (rasterize) on another thread. Recording on the main thread
> requires images to be synchronously decoded and our current focus is to
> defer image decoding to a later time and eventually have parallel image
> decoding.
>
> The specific part we overlap is drawing an asynchronously decoded
> BitmapImage to GraphicsContext. Your patch does the whole image decoding
> asynchronously while we just care about whether an image can be
> asynchronously decoded or not. This part in particular I think we should
> discuss to make sure we're both comfortable with.
>

Our approach also checks if the given image can be decoded asynchronously
or not. Please refer to "3.3 Criteria to Use Parallel Image Decoders" of
our design document. (
https://docs.google.com/document/pub?id=12gf7MhNHfupeR3GdRF-h2Vzg86viCbwXq8_JByHKlg0
)

I certainly want to hear more about your approach here.


>
> I'll make a few comments on the patch in the webkit bug.
>
>
Thanks. I think we can improve both approaches by sharing ideas with each
other regarding asynchronous image decoding because they have much in
common.

Thanks and this is great effort!
>
> Alpha
>
> 2012/7/9 KwangYul Seo <skyul at company100.net>
>
>> Hi,
>>
>> Our team at Company 100 has worked on parallel image decoders for past a
>> few weeks and some patches are pending for review now. Here is the master
>> bug for parallel image decoders:
>>
>> https://bugs.webkit.org/show_bug.cgi?id=90375
>>
>> For the overall architecture and design, please refer to the following
>> design document. We will update the design document as we change code after
>> review.
>>
>>
>> https://docs.google.com/document/pub?id=12gf7MhNHfupeR3GdRF-h2Vzg86viCbwXq8_JByHKlg0
>>
>> Our implementation shows considerable speedup in image intensive sites
>> and no performance regression in PLT. Please refer to the master bug for
>> specific numbers.
>>
>> We do understand many paralleization techniques make code so complex to
>> the level that can't be accepted. So we tried our best to reduce the
>> complexity of code, but reviewers can help us reduce it further.
>>
>> Regards,
>> Kwang Yul Seo
>>
>>
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>>
>>
>
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