Bug 43150 – Investigate using the thread pool instead of a dedicated thread for WorkQueue on Windows

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit2

[Adam Roben (:aroben)]

We should investigate using the Windows thread pool [1] instead of a dedicated thread for WorkQueue on Windows. This would be more similar to how WorkQueue works on Mac, and would hopefully improve performance overall. We'd probably implement this by using ::RegisterWaitForSingleObject.

1. http://msdn.microsoft.com/en-us/library/ms686756(v=VS.85).aspx

[Adam Roben (:aroben)]

<rdar://problem/8247280>

[Adam Roben (:aroben)]

We probably wouldn't want to do this until we had switched to using an I/O completion port in WorkQueue (bug 43148).

But I'm not so sure this will work well for us, at least not with ::RegisterWaitForSingleObject. That function will cause a new worker thread to be spawned every time the I/O completion port is signaled, even if another thread is already processing a message from the completion port. This is OK for correctness, as the worker thread will then immediately block on ::GetQueuedCompletionStatus until the other thread(s) finish their work. But it could mean that lots of threads end up sitting around blocked on ::GetQueuedCompletionStatus if it takes longer for a message to be processed than it takes for the completion port to get signaled again.

[Adam Roben (:aroben)]

Created attachment 65721 [details]
Use the Windows thread pool instead of a dedicated thread for WorkQueue on Windows

[Anders Carlsson]

Comment on attachment 65721 [details]
Use the Windows thread pool instead of a dedicated thread for WorkQueue on Windows

r+

[Adam Roben (:aroben)]

Committed r66506: <http://trac.webkit.org/changeset/66506>

[WebKit Review Bot]

http://trac.webkit.org/changeset/66506 might have broken Leopard Intel Debug (Tests)
The following changes are on the blame list:
http://trac.webkit.org/changeset/66505
http://trac.webkit.org/changeset/66506
http://trac.webkit.org/changeset/66507
http://trac.webkit.org/changeset/66508
http://trac.webkit.org/changeset/66509