Date: Wed, 24 Oct 2001 21:52:18 +0100 From: David Malone <dwmalone@maths.tcd.ie> To: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca> Cc: Anatoliy Dmytriyev <tolid@plab.ku.dk>, freebsd-stable@FreeBSD.ORG Subject: Re: UFS_DIRHASH - your opinion Message-ID: <200110242152.aa53208@salmon.maths.tcd.ie> In-Reply-To: Your message of "Wed, 24 Oct 2001 13:41:08 PDT." <200110242041.f9OKfbP47523@cwsys.cwsent.com>
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> > If you have directories which contains lots of files which are > > accessed repeatedly then it may be a win for you. > This seems like a useful feature. Should this be the default or is it > risky as LINT suggests? Hard to say. The system works by building a hash table of a directory before it is accessed. I think this is on average about as expensive as a handful of directory accesses. After that accesses to that directory should go more quickly. However, if the pattern in which you access directories is random enough you may end up not using the hash table enough to save the cost of building it. I'd guess it would be a win on most systems. If you want to see how much of a win it can be, then try making a directory with a thousand files and then deleting it. David. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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