unzip parallel, 3x faster than 7zip

Jay Norwood jayn at prismnet.com
Sat Apr 7 12:45:04 PDT 2012


On Saturday, 7 April 2012 at 17:08:33 UTC, Jay Norwood wrote:
> The mydefrag program uses the ntfs defrag api.  There is an 
> article at the following link showing how to access it to get 
> the Logical Cluster Numbers on disk for a file.  I suppose you 
> could sort your file operations  by start LCN, of the file, for 
> example during compression, and that might reduce the seek 
> related delays.
>
> http://blogs.msdn.com/b/jeffrey_wall/archive/2004/09/13/229137.aspx

I did a complete defrag of the g hard drive, then did parallel 
unzip of the tz folder with rmd, then unzipped it again with the 
parallel uzp.  Then analyzed the disk again with mydefrag. The 
analysis shows the unzip resulted in over 300 fragmented files 
created, even though I wrote each expanded file in a single 
operation. So, I did a complete defrag again, then removed the 
folder again, and get about the same 109 secs for the delete 
operation on the hd  (vs about 17 sec on the ssd for the same 
operation).  The uzp parallel unzip is bout 85 secs vs about 17.5 
sec on the ssd.

G:\>rmd tz
removing: .\tz
finished! time:109817 ms

G:\>uzp tzip.zip tz
unzipping: .\tzip.zip
finished! time: 85405 ms

G:\>rmd tz
removing: .\tz
finished! time:108387 ms

So ... it looks like the defrag helps, as the 109 sec values are 
at the low end of the range I've seen previously.  Still it is 
totally surprising to me that deleting files should take longer 
than creating the same files.

btw, here are the windows rmdir on the defragged hd and on the 
ssd drive, and the third measurement is the D  parallel rmd on 
the ssd ... much faster on D.

G:\>cmd /v:on /c "echo !TIME! & rmdir /q /s tz & echo !TIME!"
14:34:09.06
14:36:23.36

H:\>cmd /v:on /c "echo !TIME! & rmdir /q /s tz & echo !TIME!"
14:38:44.69
14:40:02.16

H:\>rmd tz
removing: .\tz
finished! time:17536 ms





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