Re: 32/64-bit transition and memory expansion
Re: 32/64-bit transition and memory expansion
- Subject: Re: 32/64-bit transition and memory expansion
- From: Nick Zitzmann <email@hidden>
- Date: Mon, 10 May 2010 16:13:50 -0600
On May 10, 2010, at 3:45 PM, Ben wrote:
> - Is Activity Monitor likely just reporting this high tide value?
Yes.
> - Is the increase in memory usage (of about 50%) normal?
Yes. Remember, long integers and pointer variables are now twice as large in 64-bit apps. And common Cocoa integer types like CFIndex and NSInteger are typedefs for long integers.
> - Either way, should I be concerned?
Two years ago I would have said yes, because when we published our first 64-bit program around that time, we had several users write in and tell us they thought the app was using too much memory. 64-bit apps were really rare back then, and people weren't used to seeing them, so we obliged and went back to 32-bit. But now, 64-bit apps are far more common than they were back then, and a lot of the bugs in Leopard's 64-bit frameworks were fixed in Snow Leopard, so now I wouldn't hold back. There is more to the transition than having a higher VM ceiling, e.g. 64-bit apps will run faster than 32-bit apps on Intel CPUs due to improvements in the ABI.
> Lastly:
> - HeapDiff reports the worst offender for memory expansion between 32/64-bit processes as NSCFDictionary. Instruments suggests it is CFBasicHash. Is CFBasicHash part of the internals for NSCFDictionary? Google doesn't have much info on this.
I think so. A lot of Foundation objects are actually class clusters, and NSDictionary is one of them.
Nick Zitzmann
<http://www.chronosnet.com/>
_______________________________________________
Cocoa-dev mailing list (email@hidden)
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:
This email sent to email@hidden