why python is slower than java?

[kosh]

On Saturday 06 November 2004 4:10 am, Alex Martelli wrote:
> with Python 2.4 beta 1 for the roughly equivalent:
>
> inputFile = file("/usr/share/dict/web2", 'r')
> outputFile = file("/tmp/acopy", 'w')
>
> outputFile.write(inputFile.read())
>
> inputFile.close()
> outputFile.close()
>

I think a generator version works even better. I did tests at various files 
sizes and overall the generator one was better and it was vastly better at 
large file sizes and overall the generator one also impacted the system less. 
The regular version which reads the whole file at once get really bad with 
large files especially if the system is being used.

I suspect the generator version should work with any size file that the os is 
capable of working with and should be resource friendly at any size.

Just thought the generator version would be a good comparison to the java 
version and strangely enough in many cases it is actually faster then the 
regular version. :)

Generator Version:
    inputFile = file("/home/kosh/KNOPPIX_V3.6-2004-08-16-EN.iso", 'r')
    outputFile = file("/tmp/acopy", 'w')

    outputFile.writelines(inputFile)

    inputFile.close()
    outputFile.close()
    
Regular Version:
    inputFile = file("/home/kosh/temp.txt", 'r')
    outputFile = file("/tmp/acopy", 'w')

    outputFile.write(inputFile.read())

    inputFile.close()
    outputFile.close()

The timing was done with python 2.3.4 on debian/sid    
    

Large File Test:
File Copied: 733499392 KNOPPIX_V3.6-2004-08-16-EN.iso

     Real       User      Sys
Gen  0m33.478s  0m4.302s  0m3.542s
Reg  2m28.029s  0m0.010s  0m4.992s  *
Reg  0m34.913s  0m0.009s  0m4.713s

* This is how long the first run took. The machine swapped
heavily. The Other time is for subsequent runs. This method
overall uses a massive ammount of ram.


Memory Usage:
    
     Virt   Res    Shr    
Gen  3816K  2364K  2524K 
Reg  703M   700M   2524K

Small File Test

File Copied: 2754459 Zope-2.7.2-0.tgz

     Real       User      Sys
Gen  0m0.049s   0m0.023s  0m0.014s
Reg  0m0.037s   0m0.009s  0m0.019s


Tiny File Test:

File Copied: 205 May temp.txt

     Real       User      Sys
Gen  0m0.012s   0m0.007s  0m0.005s
Reg  0m0.028s   0m0.009s  0m0.003s