Le 21 mai 2010 à 17:54, Keary Suska a écrit : > On May 21, 2010, at 9:18 AM, Paul Sanders wrote: > >>> Also be aware that just because memory is released, doesn't mean it is >>> returned to the system (e.g. you will not >>> see your apps memory usage go down in Activity Monitor). In fact, AFAIK, >>> it is never returned to the system, >>> except perhaps in low memory situations. >> >> I don't actually think that's true. At least, it's not what I observe. I >> think it's more accurate to say that you cannot predict when memory which >> has been allocated and then freed will be returned to the operating system, >> nor how much. It happens, I believe, in 4k pages, but probably not one at a >> time and will be heavily dependent on fragmentation of the process's heap. >> No doubt there is much more to know. >> >> I agree with the sentiment of keeping an eye on your peak memory usage. I >> use Instruments for this, and it found one instance where memory usage was >> creeping steadily up when the app was playing audio but otherwise idle. > > Maybe AFAIK should be "As Far As I have Observed", as although using tools > like instruments I have seen constant tiny increases and decreases, I have > yet to see peak memory reduce over the lifetime of an application. > Fragmentation could certainly play a role--I don't know of any means to check > that. If this truly is the issue most of the time, it seems to me that for > most practical points and purposes that the memory won't get returned anyway, > as fragmentation seems to be so common.
The heap and vmmap command line tools can give you some interesting values. (like the % of used memory in each malloc zone, and other useful stats) -- Jean-Daniel _______________________________________________ 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
