== Quote from Rainer Schuetze (r.sagita...@gmx.de)'s article > Vladimir Panteleev wrote: > > On Thu, 15 Jul 2010 11:03:57 +0300, JimBob <j...@bob.com> wrote: > > > >> VirtualAlloc returns chunks that have 'dwAllocationGranularity' > >> granularity, > >> which is 64K on every Windows OS I've used. So allocating a page, 4K, > >> will > >> actualy get you 64K. > >> > >> So using VirtualAlloc as a replacement for malloc is very wasteful unless > >> the allocations are larger that 64K. > >> > >> You might want to look at HeapCreate and it's siblings. (on windows > >> anyway) > > > > dwAllocationGranularity only controls the granularity of the allocation > > address, but not of the allocation size. A simple program that calls > > VirtualAlloc 16384 times uses up 1 GB of the address space, but only 64 > > MB of actual memory. So, while it is a waste of address space, it's not > > a waste of system memory. > In a 32-bit process, the waste of address space is sometimes more > critical nowadays. There is only 2GB virtual memory available (3GB with > some tweaks), and with the example above, VirtualAlloc fails well before > allocating 128 MB.
Yea, but I wonder how much longer it is going to be before 32-bit is dead as a dodo except on things like netbooks. Frankly, it's about time for it to die, because dealing w/ address space limitations when plenty of physical memory is available just plain sucks. DMD is in the process of being ported to 64-bit as we speak. Almost any Linux distro is available in 64-bit. IIRC (I can't remember for sure where I heard this) Windows 7 will be the last 32-bit version, and it seems like most people who have migrated use the 64-bit version. On the hardware end, 64-bit is now 6-7 years old, which has to be a standard deviation or two older than the average age at which computers get replaced.
