From owner-freebsd-current Wed Apr 25 18: 8:18 2001 Delivered-To: freebsd-current@freebsd.org Received: from bazooka.unixfreak.org (bazooka.unixfreak.org [63.198.170.138]) by hub.freebsd.org (Postfix) with ESMTP id DE09E37B423 for ; Wed, 25 Apr 2001 18:08:15 -0700 (PDT) (envelope-from dima@unixfreak.org) Received: from spike.unixfreak.org (spike [63.198.170.139]) by bazooka.unixfreak.org (Postfix) with ESMTP id 51F133E2A; Wed, 25 Apr 2001 18:08:15 -0700 (PDT) To: Garance A Drosihn Cc: "John W. De Boskey" , "David O'Brien" , Brian Somers Subject: Re: Updated: cp -t patch (w/ commentary) In-Reply-To: ; from drosih@rpi.edu on "Wed, 25 Apr 2001 14:32:04 -0400" Date: Wed, 25 Apr 2001 18:08:15 -0700 From: Dima Dorfman Message-Id: <20010426010815.51F133E2A@bazooka.unixfreak.org> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Garance A Drosihn writes: > At 10:01 AM -0400 4/25/01, John W. De Boskey wrote: > > 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. > > It is inconceivable that the proposed patch to 'xargs' would > increase your running time. I don't mean the standard '-I' > change, which would certainly destroy performance, but the > proposed patch to 'xargs' which solves your specific problem > in a general way. > > I'm still curious as to why you think the proposed change to > xargs will cause you ANY performance problem. I simply can > not imagine where you would get a performance problem from > the -Y idea (though I'm still tempted to change the letter > for that proposed option). I think everything that should have been said in this thread already has been (so I won't repeat it), except for the performace bit. As the author of the patch, I doubt it would hinder performance. All it does is move one part of a loop further down. Instead of doing something once, it does part of that job twice. This job acts on arguments *to xargs* (i.e., argv), and is nothing more than pointer arithmetic and assignment. Unless you give umpteen arguments *to xargs*, you shouldn't notice a difference in execution speed. And as you (gad) said, implementing -I the way SUSv2 defines it would most likely kill performance (most likely it'd also slow down whether you actually use that option or not). > Dimi has written one or two different patches to xargs. Did ^^^ <-- should be 'a', but that's okay. :-) One patch. Thanks, Dima Dorfman dima@unixfreak.org P.S. obrien: that's a very clever and unintrusive way of avoiding getting two copies of a message; much better than TrimYourCC@nuxi.com. Those of us (well, at least me) who actually want a copy of the message in our inbox greatly appreciate it. Thanks! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message