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Date:      Wed, 25 Apr 2001 10:01:18 -0400
From:      "John W. De Boskey" <jwd@bsdwins.com>
To:        "David O'Brien" <freebsd-current@FreeBSD.ORG>, Brian Somers <brian@Awfulhak.org>
Subject:   Re: Updated: cp -t  patch (w/ commentary)
Message-ID:  <20010425100118.A35414@bsdwins.com>
In-Reply-To: <20010425005942.A71859@dragon.nuxi.com>; from freebsd-current@FreeBSD.ORG on Wed, Apr 25, 2001 at 12:59:42AM -0700
References:  <20010423113324.A70387@FreeBSD.org> <20010425005942.A71859@dragon.nuxi.com>

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Hi David, Brian,

   Thank you for taking the time to reply. I hope you were
able to review the patch also.

   I am dealing with a production process that currently runs
approximately 10 hours. (on 28 866Mhz processors, 2 Netapps).
This process fell into my lap about 2 months ago.

   After studying the process, the 1st item that came to the
fore-front was the number of fork/exec pairs occuring for the
file copy process. Please note, as written in previous emails,
the copy process copies files from multiple directories to a
singular directory.

   I have reduced the runtime of the process so far by a solid
hour.  My change to cp is the lowest level/minimal change fix
which allows me to maintain a O(1) time constraint. I've played
with (non-freebsd) versions of xargs already, and found them
(the various algorithms in xargs) to be more expensive than the
patch to cp.

   I realize you folks are not here, and cannot examine the processes
I have to deal with first hand.  I can only simply ask you to 
trust that the work I and others have done while coming to the
conclusion that the cp patch is the best alternative is correct.


   On a different note, I have spoken with my mentor (seems funny
calling him that these days) Jordan, and his response to my
email was:

----
I think you should just commit the cp changes and let the
xargs weenies debate themselves silly if the want to. :)
The two issues are not really related.

-Jordan
----

   I must say at this point, I tend to agree with him. Basically,
my review request was skipped over and folks simply went on to
discuss/argue the merits/demerits of various patchs to xargs. The
question of whether xargs is appropriate and maintains adequate
performance for my particular process seems to have been left on
the roadside...

   I hope I haven't rambled to much. And again, thanks for taking
the time to respond.

-John


----- Current List's Original Message -----
> On Mon, Apr 23, 2001 at 11:33:24AM -0700, John W. De Boskey wrote:
> >    After some feedback, I have changed the patch slightly. Rename
> > -d to -t and remove the requirement for the option to have a
> > value.
> 
> I thought people generally agreed the right fix was to add functionality
> to `xargs', not `cp' as you aren't scratching the general itch.
>  
> -- 
> -- David  (obrien@FreeBSD.org)
> 
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