From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756668AbZFIXxt (ORCPT ); Tue, 9 Jun 2009 19:53:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753306AbZFIXxm (ORCPT ); Tue, 9 Jun 2009 19:53:42 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:55864 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753039AbZFIXxl (ORCPT ); Tue, 9 Jun 2009 19:53:41 -0400 Date: Tue, 9 Jun 2009 16:53:04 -0700 From: Andrew Morton To: Ray Lee Cc: hpa@zytor.com, renton@renton.name, linux-kernel@vger.kernel.org Subject: Re: devpts mounts too slowly Message-Id: <20090609165304.add1a872.akpm@linux-foundation.org> In-Reply-To: <2c0942db0906091630l1cc79647h8689e9e929ed1bba@mail.gmail.com> References: <20090603142801.GC21646@beaver.vrungel.ru> <4A26EB18.6060907@zytor.com> <20090609161945.811cc01f.akpm@linux-foundation.org> <2c0942db0906091630l1cc79647h8689e9e929ed1bba@mail.gmail.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Jun 2009 16:30:31 -0700 Ray Lee wrote: > On Tue, Jun 9, 2009 at 4:19 PM, Andrew Morton wrote: > > On Wed, 03 Jun 2009 14:28:56 -0700 > > "H. Peter Anvin" wrote: > > > >> Alexey Vlasov wrote: > >> > Hi. > >> > > >> > In comparison with bind/proc mounting it takes a lot more time mounting > >> > devpts. Is it possible to somehow accelerate the process? Now there are > >> > about 5k devpts mounting, it already took 20 minutes, further will take > >> > even more time. > >> > > >> > # time mount -n -i -t devpts none /home/staff/.server-1/dev/pts > >> > real __ __0m0.295s > >> > user __ __0m0.000s > >> > sys __ __ 0m0.288s > >> > > >> > >> A profile would be handy here. __There is no sensible reason for this to > >> that 0.3 seconds. __This might be RCU-epoch related? > >> > > > > It seems OK here. > > > > akpm2:/home/akpm/xx# time mount -n -i -t devpts none /tmp/pts > > mount -n -i -t devpts none /tmp/pts __0.00s user 0.00s system 0% cpu 0.002 total > > I read the Original Post as that test being performed with 5k /dev/pts > already mounted. hm, OK. I've now mounted 15000 devpts's and still no slowdown is evident.