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How to speed up reading a file ?

Charley Chen

Hi All,

 I read a file which has 1386213 line  or more , only read each line  , it spend  7 minutes  and above.

How can it speed up ?

 

procedure( QQ(file)
   prog( ()
      inPort=infile(file)
           while( gets(inLine inPort)

               ........
           ) ;if
      ) ;while
       inPort=nil
  ) ;prog
) ;procedure

 

Thank you,

Charley

Parents

  • Charley,

    I doubt it's the reading part - it's probably whatever you're doing in the ... bit. I just created a file with 1500000 lines, and then used:

    procedure( QQ(file)
       prog( ()
          inPort=infile(file)
               while( gets(inLine inPort)
                  t
              ) ;while
           inPort=nil
      ) ;prog
    ) ;procedure

    I ran this reading the file (over the network, not local disk) through the profiler, and got:

    Function Name                        Total   Inside
    -------------                        -----   ------
    TOTAL CPU Time (secs)                 1.91     1.91
    QQ                                    1.41     0.14
    toplevel                              1.41     0.00
    _gets                                 1.27     1.27
    gc                                    0.49     0.49

    So as you can see, a total of 2 seconds.

    I then generated a much bigger (longer lines) file with 1800000 lines (95Mbytes), and the profile results were:

     Function Name                        Total   Inside
    -------------                        -----   ------
    TOTAL CPU Time (secs)                 3.58     3.58
    QQ                                    2.91     0.19
    toplevel                              2.91     0.00
    _gets                                 2.72     2.72
    gc                                    0.67     0.67

    I suggest you run the SKILL profiler to see where the bottleneck is.

    Andrew.

Reply

  • Charley,

    I doubt it's the reading part - it's probably whatever you're doing in the ... bit. I just created a file with 1500000 lines, and then used:

    procedure( QQ(file)
       prog( ()
          inPort=infile(file)
               while( gets(inLine inPort)
                  t
              ) ;while
           inPort=nil
      ) ;prog
    ) ;procedure

    I ran this reading the file (over the network, not local disk) through the profiler, and got:

    Function Name                        Total   Inside
    -------------                        -----   ------
    TOTAL CPU Time (secs)                 1.91     1.91
    QQ                                    1.41     0.14
    toplevel                              1.41     0.00
    _gets                                 1.27     1.27
    gc                                    0.49     0.49

    So as you can see, a total of 2 seconds.

    I then generated a much bigger (longer lines) file with 1800000 lines (95Mbytes), and the profile results were:

     Function Name                        Total   Inside
    -------------                        -----   ------
    TOTAL CPU Time (secs)                 3.58     3.58
    QQ                                    2.91     0.19
    toplevel                              2.91     0.00
    _gets                                 2.72     2.72
    gc                                    0.67     0.67

    I suggest you run the SKILL profiler to see where the bottleneck is.

    Andrew.

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