From owner-freebsd-current@FreeBSD.ORG Tue Oct 9 13:27:20 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CC23516A418 for ; Tue, 9 Oct 2007 13:27:20 +0000 (UTC) (envelope-from is@rambler-co.ru) Received: from relay0.rambler.ru (relay0.rambler.ru [81.19.66.187]) by mx1.freebsd.org (Postfix) with ESMTP id 803B613C459 for ; Tue, 9 Oct 2007 13:27:20 +0000 (UTC) (envelope-from is@rambler-co.ru) Received: from relay0.rambler.ru (localhost [127.0.0.1]) by relay0.rambler.ru (Postfix) with ESMTP id 41E0019152 for ; Tue, 9 Oct 2007 16:50:05 +0400 (MSD) Received: from localhost (is1.park.rambler.ru [81.19.64.121]) by relay0.rambler.ru (Postfix) with ESMTP id 06660DE31 for ; Tue, 9 Oct 2007 16:50:05 +0400 (MSD) Date: Tue, 9 Oct 2007 16:50:01 +0400 From: Igor Sysoev To: freebsd-current@freebsd.org Message-ID: <20071009125001.GC5758@rambler-co.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: No virus found Subject: sendfile and page usage statistics X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Oct 2007 13:27:20 -0000 As I understand if sendfile() with hardware TX chsum or TSO are used, then CPU does not touch file pages at all. So pagedaemon never set PG_REFERENCED to vnode object pages while scanning them. Does VM set PG_REFERENCED by another way ? Otherwise, often used files that accessed by sendfile() only have small chances to be cached by VM. -- Igor Sysoev http://sysoev.ru/en/