From owner-freebsd-hackers Fri Jul 2 14:22:15 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from osgroup.com (unknown [38.229.41.6]) by hub.freebsd.org (Postfix) with ESMTP id 283AA14E67 for ; Fri, 2 Jul 1999 14:22:03 -0700 (PDT) (envelope-from stan@laurent.osgroup.com) Received: from localhost (stan@localhost) by osgroup.com (8.7.6/8.6.12) with SMTP id QAA04299; Fri, 2 Jul 1999 16:10:57 -0500 Date: Fri, 2 Jul 1999 16:10:57 -0500 (CDT) From: Stan Shkolnyy To: Dennis Cc: hackers@FreeBSD.ORG Subject: Re: mbufs question/problem In-Reply-To: <199906302150.RAA01512@etinc.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 30 Jun 1999, Dennis wrote: > > I have a customer who has been experiencing "slow downs" with a freebsd > router....they have substantially increased performance by reducing > MINCLSIZE. I havent tracked the source, but im trying to hypothesize what > it might be. On the surface I cant see any relationship since very few > routines seem dependent on that value (m_devget() in particular, but I dont > believe they are using any driver that use it). Is it possible that they > are running out of small mbufs (they have NMBCLUSTERS set to a very high > value)? > > Any ideas would be helpful. I have not noticed answers so far, so maybe their drivers copy mbufs very often. AFAIK, "small" mbufs are indeed copied but "cluster" ones are not, so when they forced the system to use more "cluster" mbufs, they got substantial savings on copy operations. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message