From owner-cvs-src@FreeBSD.ORG Thu Mar 3 20:43:54 2005 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 47AA316A4CE; Thu, 3 Mar 2005 20:43:54 +0000 (GMT) Received: from mail.vicor-nb.com (bigwoop.vicor-nb.com [208.206.78.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 12A4943D5C; Thu, 3 Mar 2005 20:43:54 +0000 (GMT) (envelope-from julian@elischer.org) Received: from [208.206.78.97] (julian.vicor-nb.com [208.206.78.97]) by mail.vicor-nb.com (Postfix) with ESMTP id D5FBA7A423; Thu, 3 Mar 2005 12:43:53 -0800 (PST) Message-ID: <42277709.2070407@elischer.org> Date: Thu, 03 Mar 2005 12:43:53 -0800 From: Julian Elischer User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.5) Gecko/20050218 X-Accept-Language: en, hu MIME-Version: 1.0 To: David Xu References: <200503021343.j22DhpQ3075008@repoman.freebsd.org> <200503020915.28512.jhb@FreeBSD.org> <4226446B.7020406@freebsd.org> <20050303033115.GA13174@VARK.MIT.EDU> <42269DB0.6070107@freebsd.org> <20050303052902.GA14011@VARK.MIT.EDU> <4226A46B.2090704@freebsd.org> <20050303060357.GA14180@VARK.MIT.EDU> <20050303001403.W811@odysseus.silby.com> <20050303064206.GA14434@VARK.MIT.EDU> <4226B4EA.40308@freebsd.org> In-Reply-To: <4226B4EA.40308@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit cc: src-committers@FreeBSD.org cc: John Baldwin cc: cvs-src@FreeBSD.org cc: Mike Silbersack cc: cvs-all@FreeBSD.org cc: David Schultz Subject: Re: cvs commit: src/sys/kern kern_sig.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Mar 2005 20:43:54 -0000 David Xu wrote: > David Schultz wrote: > >> On Thu, Mar 03, 2005, Mike Silbersack wrote: >> >> >>> On Thu, 3 Mar 2005, David Schultz wrote: >>> >>> >>> >>>> Of course, there's another possible solution which is to remove >>>> the swapping code entirely. That would certainly simplify things, >>>> but it would also make FreeBSD degrade less gracefully under load. >>>> >>> >>> I don't think that would be a big loss; by the time you're doing a >>> lot of process swapping, you're pretty screwed. >>> >>> A process has to be swapped back in in order for it to be killed, >>> right? We might be better off without swapping, in that case. >>> >> >> >> Yeah, with 16K kernel stacks, you'd have to swap a lot of threads > 16K!! we used to run on 4k, and that was with interrupts using the stack as well.. now we a e not doing that.. we should look at stack usage and get it back to 8K at most! :-) (on x86) >> to make a big difference in the amount of wired memory in the >> system. KSE helps with this, because processes with thousands of >> user threads don't have thousands of kernel threads. >> >> >> > This only happens at comparative idle time, if the process is a heavy > I/O bound process, > this does not help. assuming that all those threads are doing IO. > >> Another thing that swapping does, though, is prevent some >> processes from running for a while when the system is under load, >> thereby reducing contention for resources and allowing the other >> processes to get things done. If people decide to go this way, it >> might be a good idea to keep the second feature. It costs very >> little in terms of complexity because no actual swapping is done. >> But who knows? Maybe nobody cares about this, either... >> >> >> > I would like to not swap out kernel stack, it allows me to write some > speedy code, > this is my personal favorit. :=) I think that swapping kernel stacks may be an idea who's time has passed.