From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264075AbTEGRer (ORCPT ); Wed, 7 May 2003 13:34:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264092AbTEGRer (ORCPT ); Wed, 7 May 2003 13:34:47 -0400 Received: from wohnheim.fh-wedel.de ([195.37.86.122]:38037 "EHLO wohnheim.fh-wedel.de") by vger.kernel.org with ESMTP id S264075AbTEGReq (ORCPT ); Wed, 7 May 2003 13:34:46 -0400 Date: Wed, 7 May 2003 19:47:16 +0200 From: =?iso-8859-1?Q?J=F6rn?= Engel To: William Lee Irwin III , Torsten Landschoff , Linux kernel Subject: Re: top stack (l)users for 2.5.69 Message-ID: <20030507174716.GE19324@wohnheim.fh-wedel.de> References: <20030507132024.GB18177@wohnheim.fh-wedel.de> <20030507135657.GC18177@wohnheim.fh-wedel.de> <20030507143315.GA6879@stargate.galaxy> <20030507144736.GE8978@holomorphy.com> <20030507164901.GB19324@wohnheim.fh-wedel.de> <20030507173825.GU8931@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20030507173825.GU8931@holomorphy.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 May 2003 10:38:25 -0700, William Lee Irwin III wrote: > On Wed, May 07, 2003 at 06:49:01PM +0200, J?rn Engel wrote: > > It also matters if people writing applications for embedded systems > > have a fetish for many threads. 1000 threads, each eating 8k memory > > for pure existance (no actual work done yet), do put some memory > > pressure on small machines. Yes, it would be possible to educate those > > people, but changing kernel code is more fun and less work. > > If they're embedded and UP they can probably get by on a userspace > threading library that only creates one kernel thread. > > It's highly unlikely anyone will get anywhere "fixing" this in the > kernel. The closest approximations to mitigating the pinned memory > overhead with UNIX-style kernel semantics are swappable stacks a la the > u area and M:N threading, neither of which are popular notions. If > you're trying the other approach I mentioned in this thread, good luck > ever getting it done and good luck ever surviving even a single merge. > > $ grep -nr schedule . | wc -l > 3773 Ah, now I see where the misunderstanding comes from. My bad. I would merely like to save NO_THREADS * 4k, not the full 8k. People here are migrating from Readtime OS's to Linux, partially and I wouldn't think about introducing hard priorities into the scheduler either. "This is plain impossible." is a very good argument for education. "This only works under certain conditions." is where people always demand more, sometimes rightfully, sometimes not. Jörn -- Measure. Don't tune for speed until you've measured, and even then don't unless one part of the code overwhelms the rest. -- Rob Pike