| time cost for file reading increasing!!! same file! [message #69753] |
Mon, 08 February 2010 15:20  |
minchen
Messages: 8
Registered: February 2010
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Junior Member |
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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?
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| Re: time cost for file reading increasing!!! same file! [message #69803 is a reply to message #69753] |
Thu, 11 February 2010 13:29  |
R.G.Stockwell
Messages: 163
Registered: October 2004
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Senior Member |
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On Feb 10, 6:00 am, Bennett <juggernau...@gmail.com> wrote:
....
has this been resolved yet?
I am just curious.
my wild guess. it sounds like the time to read a file increases
by several orders of magnitude (i don't have the original post handy).
Wasn't it seconds, up to 10 minutes?
That sounds like you need to wait for something to time out before you
can make another read.
Are you making a network connection each time (then filling up all possible
connections so you queue and wait for a previous network connection to time
out)?
Something along those lines? just a thought.
cheers,
bob
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