Hi Stefan,

Thanks for the quick reply.

On Wed, Sep 22, 2010 at 10:59 AM, Stefan Kersten <[email protected]> wrote:

> hi john,
>
> On 22.09.10 11:37, John Lato wrote:
> > Initially I tried using readFileChunks, but I never got any data from it.
>  The
> > info would print out, but the calculation of the maximum value would be 0
> > because "chunks" would be an empty list.  I tried using several different
> > numbers for the first argument to readFileChunks, such as 1, 2, 8, and
> 1024 (is
> > it the number of frames to read?), but always received an empty list.
>  Could any
> > point me to what I'm doing wrong?  This is with ghc-6.12.1.
>
> you're not doing anything wrong; i think the reason is that the way
> readChunks
> is implemented the file handle is closed prematurely. this function needs
> to be
> removed from the interface.
>

Ok, then I'll try the handle version.


>
> > Now it works and reports the proper answer, but when I run the program
> with +RTS
> > -s it shows low memory usage.  Very low.
> >
> >           40,488 bytes allocated in the heap
> >            1,484 bytes copied during GC
> >            6,124 bytes maximum residency (1 sample(s))
> >           14,356 bytes maximum slop
> >                1 MB total memory in use (0 MB lost due to fragmentation)
> >
> > However, the system monitor shows that the program is occupying about
> 230MB of
> > RAM.  For my test file the this program reports:
> >
> > Info {frames = 17479453, samplerate = 44100, channels = 2, format =
> Format
> > {headerFormat = HeaderFormatWav, sampleFormat = SampleFormatPcm16,
> endianFormat
> > = EndianFile}, sections = 1, seekable = True}
> >
> > so 230MB seems consistent with allocating a single vector of Doubles.
> >
> > So my second question is, why is this memory usage not reported by +RTS
> -s, or -hT?
>
> i'm not sure either, maybe because the memory is allocated on the heap by
> malloc? this might indicate a memory leak, i'll investigate. i'm currently
> on
> the road and won't have the time to look into the problem before sunday ...


I'll try asking on haskell-cafe, maybe somebody there will know.It's not at
all urgent, so whenever you get a chance to look at it is fine by me.  I
doubt it's a memory leak in any case.

Thanks,
John
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