From owner-freebsd-hackers Thu Apr 12 9:19: 1 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from netbank.com.br (garrincha.netbank.com.br [200.203.199.88]) by hub.freebsd.org (Postfix) with ESMTP id BD9BD37B440 for ; Thu, 12 Apr 2001 09:18:56 -0700 (PDT) (envelope-from riel@conectiva.com.br) Received: from surriel.ddts.net (1-027.cwb-adsl.brasiltelecom.net.br [200.193.160.27]) by netbank.com.br (Postfix) with ESMTP id 9233E4682E; Thu, 12 Apr 2001 13:18:40 -0300 (BRST) Received: from localhost (ubzefk@localhost [127.0.0.1]) by surriel.ddts.net (8.11.2/8.11.2) with ESMTP id f3CGIbf20708; Thu, 12 Apr 2001 13:18:38 -0300 Date: Thu, 12 Apr 2001 13:18:37 -0300 (BRST) From: Rik van Riel X-Sender: riel@imladris.rielhome.conectiva To: Matt Dillon Cc: David Xu , freebsd-hackers@FreeBSD.ORG Subject: Re: vm balance In-Reply-To: <200104110244.f3B2iHk97869@earth.backplane.com> Message-ID: X-spambait: aardvark@kernelnewbies.org X-spammeplease: aardvark@nl.linux.org MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 10 Apr 2001, Matt Dillon wrote: > It's randomness that will kill performance. You know the old saying > about caches: They only work if you get cache hits, otherwise > they only slow things down. I wonder ... how does FreeBSD handle negative directory entries? That is, /bin/sh looks through the PATH to search for some executable (eg grep) and doesn't find it in the first 3 directories. The next time the script is started (it might be ran for every file in a large compile) the next invocation of the script looks for the file in 3 directories where it isn't present .. again. Does the vfs cache handle this or does FreeBSD have to go down into the filesystem code every time? Rik -- Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com.br/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message