Disable HAVE_DTRACE at build time by default for performance reasons. Also remove the JSC-related code which seems unused.
<rdar://problem/26148841>
Created attachment 278278 [details] Patch
Created attachment 278385 [details] Patch
The EWS bots are sad. Please fix.
Created attachment 278386 [details] Patch
Comment on attachment 278386 [details] Patch r=me if the bots are happy.
Comment on attachment 278386 [details] Patch Clearing flags on attachment: 278386 Committed r200568: <http://trac.webkit.org/changeset/200568>
All reviewed patches have been landed. Closing bug.
(In reply to comment #7) > Comment on attachment 278386 [details] > Patch > > Clearing flags on attachment: 278386 > > Committed r200568: <http://trac.webkit.org/changeset/200568> Changes to WebKit2 need to be reviewed and or authored by one of the people listed in <http://trac.webkit.org/browser/trunk/Source/WebKit2/Owners?rev=198224>.
Comment on attachment 278386 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=278386&action=review > Source/WebKit2/Platform/IPC/MessageRecorder.cpp:30 > +#if HAVE(DTRACE) > + It seems like the complaint here was that UUID generation in the MessageRecorder constructor had a measurable impact on performance. The right way to address this would be to either use a cheaper unique identifier (a sequence number in the low bits and the process ID in the upper bits, for example) or the generate the unique identifiers only when the DTrace probe is enabled. Pretending that OS X and iOS don’t have DTrace is an unnecessarily heavy-handed approach to take.
(In reply to comment #10) > Comment on attachment 278386 [details] > Patch > > View in context: > https://bugs.webkit.org/attachment.cgi?id=278386&action=review > > > Source/WebKit2/Platform/IPC/MessageRecorder.cpp:30 > > +#if HAVE(DTRACE) > > + > > It seems like the complaint here was that UUID generation in the > MessageRecorder constructor had a measurable impact on performance. The > right way to address this would be to either use a cheaper unique identifier > (a sequence number in the low bits and the process ID in the upper bits, for > example) or the generate the unique identifiers only when the DTrace probe > is enabled. > > Pretending that OS X and iOS don’t have DTrace is an unnecessarily > heavy-handed approach Sure, we should make this less expensive if we need to re enable DTRACE. I did discuss this with Sam and Tim (who added this code) and they agreed to disable it for now. It does not seem people (besides Tim) were using this code, it has also never really worked on iOS as far as I know.