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Date:      Sun, 15 Dec 2002 10:12:14 +0100
From:      phk@FreeBSD.ORG
To:        Nate Lawson <nate@root.org>
Cc:        Michael Ranner <mranner@inode.at>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: setattr() syscall as proposed by phk 
Message-ID:  <49290.1039943534@critter.freebsd.dk>
In-Reply-To: Your message of "Sun, 15 Dec 2002 00:50:35 PST." <Pine.BSF.4.21.0212150042291.41793-100000@root.org> 

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In message <Pine.BSF.4.21.0212150042291.41793-100000@root.org>, Nate Lawson wri
tes:
>On Sat, 14 Dec 2002, Michael Ranner wrote:
>> Hi there!
>> 
>> I have implemented the setattr(), lsetattr() and fsetattr() syscalls for
>> 4.7 and 5.0. You can review my code on http://www.ranner.jawa.at/freebsd.php.
>> 
>> Comments and suggestions are welcome.
>
>I don't mean to be rude but I doubt the utility of this whole
>plan.  dump/restore are done on disk devices which are at least an order
>of magnitude slower than a syscall boundary crossing.  Going from 4
>syscalls to 1 can't make a bit of difference in restore(8) performance.

You are wrong about restore:  restore is done on a mounted filesystem.

>So why is this faster?  Something is likely slowing namei() down.  

Because 1 syscall and 2 namei calls are faster than 4 syscalls and
four namei calls.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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