On Jan 31, 2011, at 5:13 PM, Peter Lübke wrote: > I use a worker thread in my app that invokes the same method(s) on all > objects in an array sent from the main thread. The array may contain > thousands of objects. > The main thread communicates with the worker thread via distributed objects. > > Everything works fine except performance is too slow. > Seems to me that my NSConnection asks for the method signature each time the > method is invoked on an object in the array, thus adding massive overhead.
Well, that's part of it, but probably not the biggest part. The way you're using D.O. defeats the purpose of having a worker thread. Sending the array from the main thread to the worker thread causes the worker thread to receive a proxy for the array. Then, as you request each element of the array, that's a message to the main thread and back, and what you get is... a proxy for the element (not the element itself). Then, every operation you perform on the element is a message to the main thread _and the main thread performs the work on behalf of its "client"_. So, you have effectively failed to shift the work from the main thread to the worker thread. The main thread is a "server" doing all of the work on the behalf of its client, the worker thread. If you're going to use D.O., ideally you want the messages to either carry no data or to carry data values (bycopy), not references to objects. Also, you want to design a fairly coarse-grained protocol of requests that a client can make of the server -- few requests to do some big chunks of work, not many requests for small chunks of work. > The shared objects approach - call NSThread's > -detachNewThreadSelector:toTarget:withObject: with the array as argument 3, > have the secondary thread do the job and exit - is way faster! Is there a reason that's not sufficient? Why are you trying to use D.O.? Regards, Ken _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
