Date: Thu, 7 Feb 2002 22:30:18 +0000 From: David Malone <dwmalone@maths.tcd.ie> To: Alfred Perlstein <bright@mu.org> Cc: Henk Wevers <henk@wevers.org>, freebsd-hackers@freebsd.org Subject: Re: vfs.ufs.dirhash_docheck? Message-ID: <20020207223018.GB67018@walton.maths.tcd.ie> In-Reply-To: <20020207124157.K3623@elvis.mu.org> References: <3C62DC57.5050703@wevers.org> <20020207124157.K3623@elvis.mu.org>
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On Thu, Feb 07, 2002 at 12:41:57PM -0800, Alfred Perlstein wrote: > * Henk Wevers <henk@wevers.org> [020207 11:58] wrote: > > Just to try the "thing" out i did put vfs.ufs.dirhash_docheck to 1. > > My active memory use was in 30 minutes 75 MB lower, and the io is > > faster, the load is lower. > > The OS is FreeBSD 4.5-REL with 1250MB ram on a PIII 733, it runs 30+ > > active jail() enviorements. > > > > What does it exactly, this hidden sysctl value? > > It's a debugging sysctl that is wasting cpu cycles. Turn it off, > don't touch the flashing lights and keep your dirty mitts away > from the big red button. Actually, Ian told me that it enables some secret inline assembley that increases the RPM of your hard disk and defragments the microcode on the CPU... Another good tip is to regurally unplug the RJ45 from your ethernet card and clean out the socket with a old toothbrush. It gets rid of any ether which has built up due to heave network usage. ;-) But seriously, as Alfred says - it enables some extra sanity checks in the dirhash code. It shouldn't make any difference, except that it burns a few CPU cycles. David. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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