Re: [Discuss-gnuradio] Windows Port Error

[Stephane Fillod]

Hi Joshua,

Thanks for the reply. Unfortunately, the code already takes care
of using a 64k granularity. Could it be some bigger granularity
is needed?

-- 
Stephane

On Thu, Jan 12, 2006 at 05:05:50PM -0800, Joshua Lackey wrote:
> I don't have the GNU Radio code in front of me, so I'm not sure if this
> is the problem, but MSDN says that the lpBaseAddress (the last argument)
> is rounded down to a multiple of the system's memory allocation
> granularity.  (Which is most likely 64k.)
> 
> Is vmcircbuf using at least 64k buffers?  Actually, it would have to be
> exactly 64k (or a multiple of 64k anyway) for this to work at all.  If
> the buffer is less, then the address would be rounded down to the same
> address you got before.  Try setting the buffer size to 64k and
> recompile.
> 
> 
> Quoting Stephane Fillod (address@hidden):
> > Hi Chris,
> > 
> > 
> > On Thu, Jan 12, 2006 at 11:18:30AM -0500, Robert Roberts wrote:
> > > I ran test_vmcircbuf.exe  several times and each time I get the same 
> > > results, shown below.
> > > 
> > > Testing gr_vmcircbuf_createfilemapping_factory...
> > > gr_vmcircbuf_mmap_createfilemapping: non contiguous mmap 003F0000 
> > > 003F0000 00010000 00400000
               ^^^^^^^^
> > 
> > Ah! looking at 
> > gnuradio-core/src/lib/runtime/gr_vmcircbuf_createfilemapping.cc
> > one can see your Windows XP is trying to outsmart us!
> > How can it be? Well, the code trys to make 2 (different) mappings of 
> > the same offset inside paging file. It looks like the OS ignores
> > the last argument of MapViewOfFileEx, which is the desired virtual
> > address of the mapping. Instead of giving a brand new address (which
> > could have been non-contiguous when last argument of MapViewOfFileEx 
> > is ignored), the OS returns the very same virtual address of the
> > first mapping, which has same offset. That's smart, but that's not 
> > what we want!
> > 
> > So, to sumarise, the machine has a 64-bit CPU (Opteron) with a bunch of 
> > RAM (>2GB), and a 32-bit OS, Windows XP SP2. Does anyone else on the list
> > encountered the same problem under Windows? More important, does anyone
> > with a similar machine (Opteron+Windows XP SP2) managed to get GNU Radio
> > to work?
> > 
> > I have no clue on how to fix this. Can somebody help? Would someone
> > familiar with Windows support forums be keen to ask why MapViewOfFileEx
> > does not work as expected, and what alternative we have?
> > 
> > -- 
> > Stephane