Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 20 Apr 2002 06:15:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 20 Apr 2002 06:15:24 -0400 Received: from sv1.valinux.co.jp ([202.221.173.100]:54281 "HELO sv1.valinux.co.jp") by vger.kernel.org with SMTP id ; Sat, 20 Apr 2002 06:15:23 -0400 Date: Sat, 20 Apr 2002 19:14:19 +0900 (JST) Message-Id: <20020420.191419.35011774.taka@valinux.co.jp> To: habanero@us.ibm.com Cc: trond.myklebust@fys.uio.no, linux-kernel@vger.kernel.org Subject: Re: [PATCH] zerocopy NFS updated From: Hirokazu Takahashi In-Reply-To: <200204192128.QAA24592@popmail.austin.ibm.com> X-Mailer: Mew version 2.2 on Emacs 20.7 / Mule 4.0 (HANANOEN) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, > With all this talk on serialization on UDP, and have a question. first, let > me explain the situation. I have an NFS test which calls 48 clients to read > the same 200 MB file on the same server. I record the time for all the > clients to finish and then calculate the total throughput. The server is a > 4-way IA32. (I used this test to measure the zerocopy/tcp/nfs patch) Now, > right before the test, the 200 MB file is created on the server, so there is > no disk IO at all during the test. It's just an very simple cached read. > Now, when the clients use udp, I can only get a run queue length of 1, and I > have confirmed there is only one nfsd thread in svc_process() at one time, > and I am 65% idle. With tcp, I can get all nfsd threads running, and max all > CPUs. Am I experiencing a bottleneck/serialization due to a single UDP > socket? What version do you use? 2.5.8 kernel has a problem in readahead of NFSD. It doesn't work at all. It can be easy to fix. Thank you, Hirokazu Takahashi. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/