[SciPy-User] Strange memory limits
Tue Mar 29 12:39:35 CDT 2011
On 3/29/2011 10:31 AM, Chris Weisiger wrote:
> Thanks for the information, all. Annoyingly, I can't allocate 3
> individual 735x512x512 arrays (each ~360MB) -- the third gives a memory
> error. If I allocate 1024x1024 byte arrays (thus, each 1MB), I can make
> 1500 before getting a memory error. So I'm definitely running into
> *some* issue that prevents larger blocks from being allocated, but I'm
> also hitting a ceiling well before I should be.
> I had thought that Windows allowed for 3GB address spaces for 32-bit
> processes, but apparently (per
> ) that only applies if the program has IMAGE_FILE_LARGE_ADDRESS_AWARE
> and 4GT set...sounds like I'd need a recompile and some system tweaks to
> set those. The proper, and more work-intensive, solution would be to
> make a 64-bit build.
> My (admittedly limited) understanding of memory fragmentation was that
> it's a per-process problem. I'm seeing this issue immediately on
> starting up the program, so the program's virtual memory address space
> should be pretty clean.
> On Tue, Mar 29, 2011 at 10:14 AM, Christopher Barker
> <Chris.Barker@noaa.gov <mailto:Chris.Barker@noaa.gov>> wrote:
> On 3/28/11 4:51 PM, David Baddeley wrote:
> > what you're probably running into is a problem with allocating a
> > continuous block of memory / a memory fragmentation issue.
> On 3/28/11 8:01 PM, Charles R Harris wrote:
> > Windows 32 bit gives you 2GB and keeps the rest for itself.
> right -- I've had no problems running the same code with 32 bit python
> on OS-X that crashes out with memory errors on Windows -- similar
> > Compiling as 64 bit might solve your problem, as, with 12 GB of
> > there will be a larger address space to look for contiguous blocks in,
> > but probably doesn't address the fundamental issue.
> Ah, but while you still may only have 12GB memory, with 64 bit Windows
> and Python, the virtual memory space is massive, so I suspect you'll be
> fine. Using 1GB memory buffers on 32bit is certainly pushing it.
> > I suspect you could
> > probably get away with having much smaller contiguous blocks (eg
> have 3
> > separate arrays for the 3 different cameras) or even a new array for
> > each image.
> That would make it easier for the OS to manage the memory well.
> Christopher Barker, Ph.D.
> Emergency Response Division
> NOAA/NOS/OR&R (206) 526-6959 voice
> 7600 Sand Point Way NE (206) 526-6329 fax
> Seattle, WA 98115 (206) 526-6317 main reception
> Chris.Barker@noaa.gov <mailto:Chris.Barker@noaa.gov>
software lists, among other useful information, the sizes of contiguous
blocks of memory available to a process. You'll probably find that 64
bit Python lets you use a much larger contiguous block than 32 bit Python.
It could help to create large numpy arrays early in the program, e.g.
before importing packages or creating other arrays.
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