Date: Wed, 25 Apr 2001 18:08:15 -0700 From: Dima Dorfman <dima@unixfreak.org> To: Garance A Drosihn <drosih@rpi.edu> Cc: "John W. De Boskey" <jwd@bsdwins.com>, "David O'Brien" <freebsd-current@FreeBSD.ORG>, Brian Somers <brian@Awfulhak.org> Subject: Re: Updated: cp -t patch (w/ commentary) Message-ID: <20010426010815.51F133E2A@bazooka.unixfreak.org> In-Reply-To: <p05100c03b70ca78af686@[128.113.24.47]>; from drosih@rpi.edu on "Wed, 25 Apr 2001 14:32:04 -0400"
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Garance A Drosihn <drosih@rpi.edu> 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
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