Comments on: objc_msgSend

By: Gil Megidish

Gil Megidish — Sat, 19 Jun 2010 12:57:52 +0000

Pretty awesome post. I’m trying to debug why my iPhone game runs so slow. 88% of the time is spent in objc_msgSend, thanks for explaining, I think I know how I can kill it

Cheers

By: Anonymous

Anonymous — Tue, 05 Feb 2008 07:21:06 +0000

By: rjt

rjt — Tue, 23 May 2006 01:02:27 +0000

Got 78.5 million using the stock code on a iMac Core Duo (1.83 GHz). Smoking.

By: Patrik

Patrik — Tue, 10 Jan 2006 02:07:06 +0000

Qsort: I recall a habit writing true / two-way-bubblesort all time I wanted to sort something; this for avoiding some qsort implementation eating the stack. But maybe this only did matter on old systems with stack-limitations like 64K. Guess this also can make sense in some embedded systems with only tiny stacks avail.

By: Mike

Mike — Wed, 21 Dec 2005 20:41:07 +0000

Wow!

By: Clyde Deda

Clyde Deda — Tue, 16 Aug 2005 15:12:39 +0000

I ran this on my 1.67 G4 laptop.
Got 20 mil for the test, if i cash the function call i get 40 mil, that is fast folks.

IMP functionCall = [foo methodForSelector:@selector(increment)];
for (;;) {functionCall(foo, @selector(increment));}

Java gets 21 mil calls, but crawls to 300 thousand when doing dynamic method calls.
Method method = foo.getClass().getMethod(“increment”, parameterTypes);
return method.invoke(receiver, argumentList);

Objective-C is cool.

By: Henry Mason

Henry Mason — Thu, 11 Aug 2005 08:42:33 +0000

In order to use qsort(), you’d use -methodForSelector:, which would perform the procedure lookup only once, completely bypassing objc_msgSend().

By: Mike

Mike — Wed, 03 Aug 2005 11:08:46 +0000

since qsort is a general use algortithm (i.e. it doesn’t know anything about the data being sorted) it uses various function calls to do the comparison of elements based on the data type.

By: Erik M. Buck

Erik M. Buck — Tue, 02 Aug 2005 13:54:29 +0000

There is a lot of related information at http://www.mulle-kybernetik.com/artikel/Optimization/

In particular, there are interesting ideas for optimizing objc_msgSend() at http://www.mulle-kybernetik.com/artikel/Optimization/opti-9.html

By: Duncan mak

Duncan mak — Tue, 02 Aug 2005 07:21:02 +0000

This is interesting:

http://www.cincomsmalltalk.com/userblogs/vbykov/blogView?showComments=true&entry=3300398515