| Re: time cost for file reading increasing!!! same file! [message #69808 is a reply to message #69721] |
Thu, 11 February 2010 08:56  |
minchen
Messages: 8
Registered: February 2010
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Junior Member |
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Both 7.0 and 7.1 are tried.
On Feb 10, 6:00 am, Bennett <juggernau...@gmail.com> wrote:
> On Feb 9, 1:22 pm, minchen <mchen...@gmail.com> wrote:
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>> I think this is not the reason. Since the speed is slow down with
>> time. At later time, it may cost 10 minutes to read a file. At fist is
>> less than 0.1s.
>
>> On Feb 8, 6:04 pm, wlandsman <wlands...@gmail.com> wrote:
>
>>> On second thought, the OP is only reading, not writing, to disk, so
>>> the memory cache may not be relevant.
>
>>> On Feb 8, 9:00 pm, wlandsman <wlands...@gmail.com> wrote:
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>>>> On Feb 8, 6:20 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.
>
>>>> I am reaching here, but maybe the problem is similar to one discussed
>>>> in an earlier thread (http://tinyurl.com/yzrvd96) where the correct
>>>> question should be "Why is the file reading so fast to start
>>>> with?" Those fast times are deceptive because the IDL thinks the I/
>>>> O operation is complete after it has passed the data to the memory
>>>> cache, but the OS has not yet written the data to disk. Once the
>>>> memory cache fills, then IDL has to wait until the data is written to
>>>> the mechanical disk, but those longer times are a better measure of
>>>> the time to write the data to disk.
>
>>>> --Wayne- Hide quoted text -
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>>> - Show quoted text -
>
> Which version of IDL are you using?- Hide quoted text -
>
> - Show quoted text -
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