+++ This bug was initially created as a clone of Bug #1144317 +++ From Talos results: http://compare-talos.mattn.ca/dev/?oldBranch=Try&oldRevs=c0ae486a7c8f&newBranch=Try&newRev=9f89885a1e84&submit=true We get a 5% regression on Windows 7 and a 10% regression on Windows XP from enabling Silk. On Windows XP, it makes more sense since we use software vsync, but investigate and understand what's going on.

On the windows profiles, it looks like we get a WM_PAINT[1] notification from the OS during a window resize, which schedules two composites [2]. On non-silk profiles, the first composite occurs early during the nsWindow::OnPaint execution. On Silk, the resize varies the first composite time from the WM_PAINT since we have to wait until vsync to composite. The regression is roughly equal the time between the first composite on non-silk profiles versus the delay for the vsync signal. However, the nsWindow doesn't listen to any messages from the compositor, so it shouldn't matter that we composite later in this case. Still investigating. [1] https://msdn.microsoft.com/en-us/library/windows/desktop/dd145213%28v=vs.85%29.aspx [2] http://mxr.mozilla.org/mozilla-central/source/widget/windows/nsWindowGfx.cpp#185 Silk http://people.mozilla.org/~bgirard/cleopatra/?zippedProfile=http://mozilla-releng-blobs.s3.amazonaws.com/blobs/Try-Non-PGO/sha512/1e8d0ee159cfae556310e9635e964312c88bb3a06d63d1561606f8575f4e2ae91c48f9553cd6e632a7101e638af9157f34c176c5dde07136b3b7661cdc8faf70&pathInZip=profile_tresize/tresize/cycle_10.sps#report=b43ddd2522869efb376b31f8d5f4f574f87198ec Master http://people.mozilla.org/~bgirard/cleopatra/?zippedProfile=http://mozilla-releng-blobs.s3.amazonaws.com/blobs/Try-Non-PGO/sha512/d743711b735b8899a42d9c9dc9ccbab28f1cafb25f3f7285a6001920319009ea491fc8a881831cba87288d0dcdf70a8a34b0424a0c0f793a4d2a44601626946e&pathInZip=profile_tresize/tresize/cycle_10.sps#report=7dc3b1ff4c364ce7c2257a825dde31299df7d6a5

Oh that's fun, I got an email this morning after the vsync compositor landed on windows. Two improvements in tp5 optimized, no regression emails.

Silk is fully enabled on OS X and there have been no regression emails, only improvements. I wonder why...

I didn't get any talos regression emails for windows silk landing, but it's all landed. I did get two emails for session restore improvements. I also didn't see any striking differences in the talos graphs so closing as WFM.