Similar to bug 216377, we need to disable hardware JPEG decoding on x86 Mac for WK1 also. Some of the pre-installed apps, which use WK1, have experienced perf regression because of hardware JPEG decoding. WebKit does not own the decision whether an image is worth hardware decoding or not. This decision depends on heuristics which are run by system underlying frameworks.
<rdar://74939829>
Created attachment 425948 [details] Patch
Comment on attachment 425948 [details] Patch Will this disable it for the whole process? Or just WebKit’s uses?
I think it will disable if for the whole process. The image decoding happens underneath WebKit. The only way to disable the HW decoding is do this globally. Do you think there will be a problem with doing this?
Comment on attachment 425948 [details] Patch You need to do this without effecting the whole process. Loading WebKit should not change the behavior of code / frameworks that happen to be running in the same app.
(In reply to Said Abou-Hallawa from comment #4) > I think it will disable if for the whole process. The image decoding happens > underneath WebKit. The only way to disable the HW decoding is do this > globally. Do you think there will be a problem with doing this? Yep. We really can't do that. You will need to ask for API/SPI to disable it on a per-call basis.
(In reply to Sam Weinig from comment #6) > (In reply to Said Abou-Hallawa from comment #4) > > I think it will disable if for the whole process. The image decoding happens > > underneath WebKit. The only way to disable the HW decoding is do this > > globally. Do you think there will be a problem with doing this? > > Yep. We really can't do that. You will need to ask for API/SPI to disable it > on a per-call basis. I agree. I think the approach of this patch is incorrect.