> On Apr 25, 2014, at 10:35 AM, Seth Willits <sli...@araelium.com> wrote: > >> On Apr 25, 2014, at 8:08 AM, Jens Alfke <j...@mooseyard.com> wrote: >> >> I’m ending up at the opposite of the received wisdom, namely: >> * dispatch_sync is a lot cheaper than dispatch_async >> * only use dispatch_async if you really need to, or for an expensive >> operation, because it will slow down all your dispatch_sync calls > > Saying "dispatch_async will slow down *all* dispatch_sync calls" throws up > red flags for me. > > In my mind there's still a possibility that You're Doing It Wrong.
FWIW, I’ve been of the opinion for a while that including dispatch_sync in the API was a mistake. Too often it becomes a crutch used without understanding, resulting in stop-start behavior across threads or cores. The correct solution is usually to rewrite the code in continuation-passing style, even if that means a cascade of blocks. Microsoft realized this when designing WinRT and _removed all the synchronous APIs_. They also added the async/await keywords to C# to avoid the seventeen-levels-of-indentation problem that plagues ObjC code. Some people at Apple agree that use of dispatch_sync is a code smell, but that if they didn't include it a hundred different re-implementations would arise, all differently broken. --Kyle Sluder _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
