cp vs copy performance over local network

Larry Hall (Cygwin) reply-to-list-only-lh@cygwin.com
Wed Sep 25 18:35:00 GMT 2013


On 9/25/2013 1:17 PM, Wm. David Bentlage wrote:
> Greetings,
>
> I've often noticed that there's a big difference in the performance
> between Cygwin cp and Windows copy over the local network -- cp
> usually takes twice as long for the same operation.  Here's an
> example:
>
> muser@A4826995 /c/Users/Muser
> $ time cmd /c copy \\\\server\\w\\cygwin.zip .
>          1 file(s) copied.
>
> real    0m7.344s
> user    0m0.015s
> sys     0m0.046s
>
> muser@A4826995 /c/Users/Muser
> $ time cp \\\\server\\w\\cygwin.zip .
>
> real    0m18.559s
> user    0m0.046s
> sys     0m2.432s
>
> muser@A4826995 /c/Users/Muser
> $ uname -a
> CYGWIN_NT-6.1-WOW64 A4826995 1.7.17(0.262/5/3) 2012-10-19 14:39 i686 Cygwin
>
> muser@A4826995 /c/Users/Muser
> $ ls -lh cygwin.zip
> -rw-r--r-- 1 muser Users 513M Sep 25 11:47 cygwin.zip
>
> Why is this?  Is there something I can do to increase the performance of cp?

Use '-l'. ;-)

There's overhead to handle POSIX permissions, etc.  Perhaps copying to a
mount point with 'noacl' would help.  Otherwise, you can see all the things
that are happening by stracing 'cp'.  It may point you to some hints/ideas.

-- 
Larry

_____________________________________________________________________

A: Yes.
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