Re: MALLOC

Tech-Archive recommends: Fix windows errors by optimizing your registry

From: Joseph M. Newcomer (newcomer_at_flounder.com)
Date: 05/30/04 

Date: Sat, 29 May 2004 22:29:07 -0400

First, dream on. The chances that you will be able to allocate 1GB of memory is
vanishingly small, even if you call VirtualAlloc.

Physical RAM size has nothing to do with the ability to allocate the memory. You need a
swapfile of a minimum of 1GB, and I would suggest 1.5GB to 2GB But you need a whopping lot
of main memory to get respectable performance.because if memory is low, you spend all your
time swapping pages in and out.

Why do you need 1GB? There are often better alternatives to such massive allocations. For
example memory-mapped files where you map a view to pieces of the file.

But while you see 2GB of virtual address space, a lot of that is already committed to
various DLLs, your heap, etc., and finding 1GB of contiguous heap is very low probability.
On end-user machines, you can assume the probability is zero.

You are more likely to be able to allocate two 0.5GB chunks, or 10 100MB chunks.

If you're seriious about needing this much memory, buy an AMD64 box, which has an 8TB user
address space.
                                        joe

On Sat, 29 May 2004 07:41:03 -0700, "VIJAY" <anonymous@discussions.microsoft.com> wrote:

>I need to allocate 1 gb of data in memory.( ram).. how do i do this??
>but if the physical ram size is small and how the data is loaded..
>any suggestion will be appreciated..
> VIJAY

Joseph M. Newcomer [MVP]
email: newcomer@flounder.com
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm

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