> On May 3, 2017, at 23:27 , Doug Hill <cocoa...@breaqz.com> wrote: > > >> On May 3, 2017, at 6:21 PM, Rick Mann <rm...@latencyzero.com> wrote: >> >> Our iOS app works with very large data buffers (hundreds of MB). As you can >> imagine, we run into issues at times. >> >> I saw some sample code that used this technique, and it got me wondering if >> this actually works around the 600 MB limitation of some iOS devices (which >> begs another question: doss the large iPad Pro with 3GB of RAM also limit >> apps to 600 MB?). >> >> -- >> Rick Mann >> rm...@latencyzero.com > > The limits of mmap should be the limits of the file system. Well, technically > it’s limited by the size_t parameter which I guess is OS specific. But these > days it should be what the VFS can handle. > > I just tried out this code snippet: > > http://www.linuxquestions.org/questions/programming-9/mmap-tutorial-c-c-511265/ > > <http://www.linuxquestions.org/questions/programming-9/mmap-tutorial-c-c-511265/> > > and set the size of the mapped file to 32GB Works fine on a Mac with 16GB of > RAM. > > It is SLOOOOOOWWWWWW however. You have to move all that data across a bus > after all. If you need to load 3GB of data from your file, I recommend making > it happen on a background thread. And make some lights blink and play a happy > tune while the user waits. > > Not sure what the limitation on some iOS devices you’re referring to. Is it > dependent on the installed RAM? Are there other artificial limits?
Yeah, at least on 1 GB iOS devices, apps are limited to 600 MB (even if there's more available). I think there are subtleties to that (e.g. maybe texture memory isn't counted), I'm not sure. -- Rick Mann rm...@latencyzero.com _______________________________________________ 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
