From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750729AbWHXHPk (ORCPT ); Thu, 24 Aug 2006 03:15:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750754AbWHXHPk (ORCPT ); Thu, 24 Aug 2006 03:15:40 -0400 Received: from py-out-1112.google.com ([64.233.166.177]:22864 "EHLO py-out-1112.google.com") by vger.kernel.org with ESMTP id S1750730AbWHXHPj (ORCPT ); Thu, 24 Aug 2006 03:15:39 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=QFIggSv8o8Z9VKYtAtNMfUrghI7kcLOZthqYGod+ehExL/FPDRN8/E0feBXVNSxnFqtIh6WmMtXEnsoJ2rM/YLh3k9uFM0VZndhz96wTW0496/gcVfVKihgvgjve5JdU1azR0Q6En92mWcEU/ZlByUOzVnQ/J2gHcDonN6rSx44= Message-ID: <4ae3c140608240015v6078fc29r287601aad7a2f1dc@mail.gmail.com> Date: Thu, 24 Aug 2006 03:15:38 -0400 From: "Xin Zhao" To: linux-kernel , linux-fsdevel@vger.kernel.org Subject: Why will NFS client spend so much time on file open? MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I did Apache benchmark and collected the performance results at the file system call level. The microbenchmark results were collected when I did "make" on Apache source code. The results are very interesting: open read Total Time (s) 21.599 15.948 Count 310274 98028 Time/Call (ms) 69.61 162.69 The results show that NFS spent even more time on file open than on file read. But this result confuses me: what does NFS do to open a file? As far as I know, it just issues a lookup() RPC to get file handle, and maybe a getattr() RPC to get file attributes. This should not take so much time. Can someone explain why this could happen? Thanks, -x