From owner-freebsd-performance@FreeBSD.ORG Sat Jul 29 00:02:41 2006 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 95D6B16A4E1 for ; Sat, 29 Jul 2006 00:02:41 +0000 (UTC) (envelope-from owensr@comcast.net) Received: from alnrmhc11.comcast.net (alnrmhc13.comcast.net [206.18.177.53]) by mx1.FreeBSD.org (Postfix) with ESMTP id F2CF543D4C for ; Sat, 29 Jul 2006 00:02:40 +0000 (GMT) (envelope-from owensr@comcast.net) Received: from desky64 (c-69-243-17-124.hsd1.va.comcast.net[69.243.17.124]) by comcast.net (alnrmhc13) with SMTP id <20060729000233b1300icvcre>; Sat, 29 Jul 2006 00:02:39 +0000 Message-ID: <003801c6b2a2$5b6687d0$0501a8c0@desky64> From: "Raymond Owens" To: Date: Fri, 28 Jul 2006 20:02:54 -0400 MIME-Version: 1.0 Content-Type: multipart/related; type="multipart/alternative"; boundary="----=_NextPart_000_0034_01C6B280.D06202C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-Mailman-Approved-At: Sat, 29 Jul 2006 01:46:28 +0000 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: question concerning proper usage of kernel variables net.bpf.bufsize and vm_kmem_size_max X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 29 Jul 2006 00:02:41 -0000 This is a multi-part message in MIME format. ------=_NextPart_000_0034_01C6B280.D06202C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sir, By hardware cache size, you are referring to the processor cache? If the = box has two processors, should the value used for cache size in this = calculation be doubled? In very general terms, what is the link between = the net.bpf.bufsize and the cache? Thanks for info.. R. B. Riddick wrote: >--- Raymond Owens wrote: > =20 > >>Questions: >>Can VM_KMEM_SIZE_MAX be set manually with sysctl? >> >> =20 >> >No, but you could set it with this procedure: >1. Insert the lines > vm.kmem_size=3D123456789 > vm.kmem_size_max=3D1234567890 >in > /boot/loader.conf > >2. reboot > >That should change those values... >(see src/sys/kern/kern_malloc.c) > >I wonder, why your box needs such a big buffer? Do u have network = traffic >bursts or so? > =20 > Regardless what purpose is for, the net.bpf.bufsize should never set above hardware cache size. The best (optimal size) is 50% - 80% of the hardware cache size, unless original BPF is modified in some way I do not know. Such high bufsize will degrade performance. --=20 ------------ Jin Guojun ----------- v --- jin@george.lbl.gov --- Distributed Systems Department http://www.dsd.lbl.gov/~jin Lawrence Berkeley National Laboratory, Berkeley, CA 94720 ------=_NextPart_000_0034_01C6B280.D06202C0--