Date: Wed, 16 Jan 2002 17:04:31 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: David Wolfskill <david@catwhisker.org> Cc: <jhb@FreeBSD.ORG>, <current@FreeBSD.ORG> Subject: RE: -CURRENT as of 14 Jan seems slow Message-ID: <20020116163247.L857-100000@gamplex.bde.org> In-Reply-To: <200201160056.g0G0u3A08394@bunrab.catwhisker.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 15 Jan 2002, David Wolfskill wrote: > >Date: Tue, 15 Jan 2002 16:46:17 -0800 (PST) > >From: John Baldwin <jhb@FreeBSD.org> > >Two questions: > > >1) Do you have WITNESS on in your kernel config? > > Yes, in both the build machine & the laptop -- since before I made a > "local" hierarchy within my CVS repository (September 9, 2001). > > >2) If yes, have you tried building with a kernel without witness? > > No, not since I put it in to re-sync with GENERIC. I could try that, I > suppose -- but as noted, I've had WITNESS in there for a while; something > seems to have changed during that one 24-hr. period that affected things > rather radically. And I thought it notable. :-} > > I gather no one else has noticed this? File locking seems to cause only the usual few percent of slowdown for each round of major locking changes. I haven't completed benchmarking the file locking pessimizations. I don't use WITNESS or INVARIANTS for benchmarking of course. Maybe the file locking changes cause much larger pessimizations when WITNESS is turned on than most locking changes. I can see how they might: WITNESS seemed to slow down creation and destruction of mutexes more than most mutex operations last time I checked, and there is a descriptor for each file and each file descriptor. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020116163247.L857-100000>