Re: Memory "weight" of objects
Re: Memory "weight" of objects
- Subject: Re: Memory "weight" of objects
- From: John Stiles <email@hidden>
- Date: Sun, 04 Dec 2005 18:46:59 -0800
That's true, but your original post was already a perfect answer to the
question being asked.
Even if the NSData struct is only 1 byte long, malloc(1) is going to
bite off a 16-byte chunk since that's the minimum allocation size
(IIRC!). So in terms of "how much memory does this allocation consume,"
well, it takes up 16 bytes, because malloc_size(malloc(1)) == 16.
Daniel Jalkut wrote:
I suppose I should add a disclaimer that the numbers returned by
malloc_size might be larger than actually used by the object. It's
probably always rounded up to whatever malloc's block sizes are. I
don't know if NSObject instances are small enough to share a single
16 byte memory block, though.
Daniel
On Dec 4, 2005, at 4:54 PM, Daniel Jalkut wrote:
Hi Felix. You can answer this for any object you're curious about
using the "malloc_size" function. You can even do it from the GDB
command line:
(gdb) call (long)malloc_size((void*)[NSObject alloc])
$10 = 16
(gdb) call (long)malloc_size(@"1")
$11 = 16
(gdb) call (long)malloc_size((void*)[NSData dataWithBytes:"1"
length:1])
$12 = 32
Of course, the data itself is stored separate from the object, but I
assume you're looking for baseline values since you specified "1
char" values.
Daniel
On Dec 4, 2005, at 4:45 PM, Felix Schwarz wrote:
Hi,
I'm wondering, how much memory does an instance of a
NSObject (to know about the common "base weight" of an object)
NSString (1 character)
NSData (1 byte)
..
approximately occupy?
Felix
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