From owner-freebsd-hackers@FreeBSD.ORG Tue Nov 22 15:29:11 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 517EA106564A for ; Tue, 22 Nov 2011 15:29:11 +0000 (UTC) (envelope-from nonesuch@longcount.org) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id E04188FC20 for ; Tue, 22 Nov 2011 15:29:10 +0000 (UTC) Received: by bkbzs8 with SMTP id zs8so454384bkb.13 for ; Tue, 22 Nov 2011 07:29:09 -0800 (PST) MIME-Version: 1.0 Received: by 10.205.128.15 with SMTP id hc15mr19166586bkc.110.1321975749409; Tue, 22 Nov 2011 07:29:09 -0800 (PST) Received: by 10.223.70.205 with HTTP; Tue, 22 Nov 2011 07:29:09 -0800 (PST) X-Originating-IP: [209.66.78.50] Date: Tue, 22 Nov 2011 10:29:09 -0500 Message-ID: From: Mark Saad To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=UTF-8 Subject: Approaching the limit on PV entries X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Nov 2011 15:29:11 -0000 Hello All I want to get to the bottom of a warning in dmesg. On 7.2-RELEASE and 7.3-RELEASE I have seen the following warning in dmesg. Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl. So looking around I see a few posts here and there about how to tune the sysctls to address the warning however I am not 100% sure what each value does. It appears changing vm.pmap.shpgperproc affects the value of vm.pmap.pv_entry_max . Can someone explain the relationship of the two sysctls. Also what pitfalls of changing them are. Also why would setting kern.ipc.shm_use_phys=1 effect the pv entries. Is this supposed to lower the pv entries ? Some details on the systems where I saw this. FreeBSD 7.3-RELEASE-p5 amd64 2G RAM + 2G SWAP 1 single core opteron Superpages are enabled The servers are high traffic web-servers serving static content. tunings kern.ipc.maxsockbuf=2097152 kern.ipc.nmbclusters=32768 kern.ipc.somaxconn=1024 kern.maxfiles=131072 kern.maxfilesperproc=32768 net.inet.tcp.inflight.enable=0 net.inet.tcp.path_mtu_discovery=0 net.inet.tcp.recvbuf_max=2097152 net.inet.tcp.sendbuf_max=2097152 net.isr.direct=1 vm.pmap.shpgperproc=600 vfs.read_max=64 http://lists.freebsd.org/pipermail/freebsd-hackers/2009-December/030193.html http://lists.freebsd.org/pipermail/freebsd-hackers/2009-July/029076.html http://forums.freebsd.org/showthread.php?t=17786 -- mark saad | nonesuch@longcount.org