From owner-freebsd-net Fri Jul 12 19: 8:42 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6B7E837B400 for ; Fri, 12 Jul 2002 19:08:40 -0700 (PDT) Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id B4CC343E42 for ; Fri, 12 Jul 2002 19:08:39 -0700 (PDT) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id WAA07789; Fri, 12 Jul 2002 22:08:37 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.6/8.9.1) id g6D287n43440; Fri, 12 Jul 2002 22:08:07 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15663.35719.282690.983639@grasshopper.cs.duke.edu> Date: Fri, 12 Jul 2002 22:08:07 -0400 (EDT) To: Bosko Milekic Cc: Julian Elischer , freebsd-net@FreeBSD.ORG Subject: Re: mbuf external buffer reference counters In-Reply-To: <20020712213737.A7548@unixdaemons.com> References: <20020712122811.GA52803@hades.hell.gr> <15663.24169.445698.304534@grasshopper.cs.duke.edu> <20020712213737.A7548@unixdaemons.com> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Bosko Milekic writes: <...> > If we decide to allocate jumbo bufs from their own seperate map as > well then we have no wastage for the counters for clusters if we keep > them in a few pages, like in -STABLE, and it should all work out fine. That sounds good. > For the jumbo bufs I still maintain that we should keep the counter > for them at the end of the buf because the math works out (see my post > in that thread with the math example) and because their total size is > not a power of 2 anyway. They'll also be more randomly spread out and > use more cache slots. How about, as (I think it was) John suggested, putting the counters at the front of the buffer so they'd be close to the headers, etc in the cache and would be less likely to cause their own unique cache miss when you access them? Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message