| Re: time cost for file reading increasing!!! same file! [message #69749 is a reply to message #69748] |
Mon, 08 February 2010 17:16   |
Robert Moss, PhD
Messages: 29
Registered: November 2006
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Junior Member |
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On Feb 8, 8:05 pm, minchen <mchen...@gmail.com> wrote:
> I use:
> mem=memory(/current)
> print,mem
>
> inside the loop, and the 'print,mem' always the same value
> and I also use the top command in the system to check the occupied
> memory, it does not change.
>
> On Feb 8, 4:58 pm, Chris <beaum...@ifa.hawaii.edu> wrote:
>
>> 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- Hide quoted text -
>
>> - Show quoted text -
>
>
Is this a local disk, or a network drive? Is it local but shared by
other users? Your problem could potentially be caused by network
traffic or other folks hitting the same drive.
r
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