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To: cygwin AT cygwin DOT com
Subject: Re: Speed of Cygwin's cp vs. Windows Explorer
References: <942b10df0705120623r391f6bdeg7aaf5643901a03b0 AT mail DOT gmail DOT com> 	<46463434 DOT 2060909 AT byu DOT net>
From: ls-cygwin-2006 AT m-e-leypold DOT de
Date: Sun, 13 May 2007 15:18:08 +0200
In-Reply-To: <46463434.2060909@byu.net> (Eric Blake's message of "Sat, 12  May 2007 15:40:04 -0600")
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Eric Blake <ebb9 AT xxx DOT xxx> writes:

> According to Bob Heckel on 5/12/2007 7:23 AM:
>> Why would using Cygwin's cp to copy a large file from one Windows XP
>> box to another take 30 minutes but take only 10 minutes if I use drag
>> 'n' drop (via Explorer)?
>
> It has been mentioned in the past, and one of the ideas was adding support
> for posix_fadvise (added in the snapshots, but not in 1.5.x) and making
> coreutils take advantage of it to give Windows better hints about how the
> data being manipulated will be laid out.  I have not yet had time to play
> with this idea further, and the upstream coreutils maintainers are
> reluctant to rely on posix_fadvise just yet (since Linux currently has a
> bug where stating a file is read-once flushes it from the os cache for ALL
> processes, rather than just the process that is only going to read it
> once, which makes the read-once hint rather useless).

I thought that was what software configuration (and autoconf) was for:
-DHAVE_DEFECTIVE_fadvise or something like that should just remove the
support from coreutils like (AFAIR) you can remove use of mmap() too.


>> I'm in a position of defending the use of Cygwin instead of the manual
>> Windows way of doing things by those not familiar with Unix.  Any
>> hints would be appreciated.
>
> At least cygwin cp preserves permissions correctly.  Windows drag-n-drop
> has the annoying tendency of marking everything executable.

:-)

Regards -- Markus


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