Re: [Discuss-gnuradio] Windows Port Error

[Joshua Lackey]

Perhaps the Opteron has a larger granularity?  Should be simple to test.
(I'd do it but I don't have an Opteron, just an Athlon.)

Just to clarify, does this work under Windows with other hardware?


Quoting Stephane Fillod (address@hidden):
> 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
> 
> 
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-- 
Joshua Lackey, PhD. -- address@hidden