Just because you are using Core Foundation interfaces doesn’t mean you aren’t getting Objective-C code behind the scenes.
On Apr 26, 2014, at 2:44 PM, ChanMaxthon <xcvi...@me.com> wrote: > Also when you are using custom run loop sources (which is required here) > pretty much all code that is interfacing the run loop is CF code, so no > Objective-C method calls here (and the few remained ones can be IMP-cached so > they are just as fast.) > > Sent from my iPad > >> On Apr 27, 2014, at 5:36 AM, Jens Alfke <j...@mooseyard.com> wrote: >> >> >>> On Apr 26, 2014, at 2:10 PM, ChanMaxthon <xcvi...@me.com> wrote: >>> >>> Since you are interfacing with database maybe you can use a little >>> transaction interface which is its own thread and run loop. That may be >>> able to cut down your amount of syscalls. That is, not using GCD but old >>> fashioned NSThread, NSRunLoop (and CFRunLoop) and NSCondition. >> >> I’m pretty sure NSRunLoop has more overhead than a dispatch_queue does. It’s >> doing more work and it’s using Obj-C messaging. >> >>> OS X implemented GCD at kernel level which introduced lots of syscalls >>> which are super expensive. The old school method is largely user land so it >>> may help a little by keeping syscalls to a minimum. @synchronized uses >>> Objective-C runtime functions which was once code behind those old school >>> classes. >> >> That's the opposite of what the docs say: "A dispatch semaphore works like a >> traditional semaphore, except that when the resource is available, it takes >> less time to acquire a dispatch semaphore. The reason is that Grand Central >> Dispatch does not call into the kernel for this particular case. It calls >> into the kernel only when the resource is not available and the system needs >> to park your thread until the semaphore is signaled.” —Concurrency >> Programming Guide >> >> —Jens > _______________________________________________ > > 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/david.duncan%40apple.com > > This email sent to david.dun...@apple.com -- David Duncan _______________________________________________ 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
