getStats for logging is done in the main thread. It then does a synchronous call to the signaling thread. In case the signaling thread is busy, the main thread will be blocked. It might be better to post a task instead to the signaling thread so as not to block main thread.
Created attachment 315140 [details] Patch
rdar://problem/32515212
We could contemplate to do that for all calls but getStats is the one that will usually happen most often during the calls where there might be bottleneck issues
Comment on attachment 315140 [details] Patch Clearing flags on attachment: 315140 Committed r219359: <http://trac.webkit.org/changeset/219359>
All reviewed patches have been landed. Closing bug.