From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267521AbUIBFoD (ORCPT ); Thu, 2 Sep 2004 01:44:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267520AbUIBFoC (ORCPT ); Thu, 2 Sep 2004 01:44:02 -0400 Received: from smtp110.mail.sc5.yahoo.com ([66.163.170.8]:17828 "HELO smtp110.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S267521AbUIBFnx (ORCPT ); Thu, 2 Sep 2004 01:43:53 -0400 Date: Wed, 1 Sep 2004 22:43:06 -0700 From: "David S. Miller" To: Andi Kleen Cc: vatsa@in.ibm.com, davem@redhat.com, netdev@oss.sgi.com, linux-kernel@vger.kernel.org, dipankar@in.ibm.com, paulmck@us.ibm.com Subject: Re: [RFC] Use RCU for tcp_ehash lookup Message-Id: <20040901224306.7dd80458.davem@davemloft.net> In-Reply-To: <20040831135419.GA17642@wotan.suse.de> References: <20040831125941.GA5534@in.ibm.com> <20040831135419.GA17642@wotan.suse.de> Organization: DaveM Loft Enterprises X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; sparc-unknown-linux-gnu) 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 On Tue, 31 Aug 2004 15:54:20 +0200 Andi Kleen wrote: > And it should also fix the performance problems with > cat /proc/net/tcp on ppc64/ia64 for large hash tables because the rw locks > are gone. Time to convert netstat et al. over the netlink too. > > - I presume that one of the reasons for keeping the hash table so big is to > > keep lock contention low (& to reduce the size of hash chains). If the lookup > > is made lock-free, then could the size of the hash table be reduced (without > > adversely impacting performance)? > > Definitely worth trying IMHO. The current hash tables are far > too big. I would do that as followon patches though. The hashes are big to make the hash effective, not to help the locking contention.