Re: Cocoa application running very slow under 64 bit
Re: Cocoa application running very slow under 64 bit
- Subject: Re: Cocoa application running very slow under 64 bit
- From: Frank Illenberger <email@hidden>
- Date: Thu, 11 Sep 2008 17:47:04 +0200
As I understand it, try/catch blocks should be very fast (zero cost)
in the 64 bit evironment. As I can't observe the generation of any
exceptions, there has to be some other reason for the slow
performance. I can't find any documentation about
objc_addExceptionHandler, so I don't know if it is only called when
there are exceptions. Telling from the Shark trace, I guess the time
is spent generating backtraces. But for what purpose?
8.9% libgcc_s.1.dylib _Unwind_GetIPInfo
7.6% libgcc_s.1.dylib _Unwind_GetIPInfo
7.6% libgcc_s.1.dylib _Unwind_Backtrace
7.6% libobjc.A.dylib objc_addExceptionHandler
7.5% Unknown Library _CFDoExceptionOperation
7.2% Unknown Library _NSAppKitLock
1.5% Unknown Library -[NSView nextKeyView]
1.2% Unknown Library -[NSView _primitiveSetNextKeyView:]
Am 11.09.2008 um 15:07 schrieb Matt Gough:
On 11 Sep 2008, at 14:49, Frank Illenberger wrote:
I breaked at objc_addExceptionHandler and it gets called a lot.
Here are some example traces:
...
I guess this is normal behavior as these are regular cocoa calls.
But why does this consume so much CPU time?
Cheers
Dunno, maybe now that the Obj-C exception ABI is the same as the C++
one for 64-bit apps, there is a lot of extra stuff that needs
preparing in case the exception is going to be caught by some C++
code.
Matt
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