| Re: time cost for file reading increasing!!! same file! [message #69752 is a reply to message #69751] |
Mon, 08 February 2010 16:58   |
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Chris[6]
Messages: 84
Registered: July 2008
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On Feb 8, 1:20 pm, minchen <mchen...@gmail.com> wrote:
> Hi everyone,
> I meet a mysterious problem on IDL file reading.
> The problem is as following:
> I just read the same hdf5 file seveal times and see the time costing.
> I find the first 270 file reading is very quickly but after that, the
> reading speed drops down although the file is the same one.
>
> The simple code is here:
> pro try
> filename='./particles.h5'
> file_id=h5f_open(filename)
> for i=1,2 do begin
> i=1 ; here just for test, so it will
> always read
> print,'Systime=',Systime(0) ; here output the systime
> dataset_name='Electrons_at_PE_302'
> dataset_id=h5d_open(file_id,dataset_name)
> ptcl0=h5d_read(dataset_id)
> h5d_close,dataset_id
> endfor
> h5f_close,file_id
> end
>
> I have check the memory, it does not increase. So the memory should no
> problem.
> Why the reading time increase? I am also sure there is no problem with
> the hard disk heating.
> So, what's the problem?
What does your system memory look like? I don't know anything about
h5d_read, but if there is a memory leak, you could be running low on
RAM. Try adding in a line like
help,/memory
to the interior of the loop. None of the numbers should increase over
time unless you are leaking memory.
chris
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