From owner-cvs-all@FreeBSD.ORG Mon Oct 29 21:58:54 2007 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E4ED316A417; Mon, 29 Oct 2007 21:58:54 +0000 (UTC) (envelope-from deischen@freebsd.org) Received: from mail.netplex.net (mail.netplex.net [204.213.176.10]) by mx1.freebsd.org (Postfix) with ESMTP id A459213C48A; Mon, 29 Oct 2007 21:58:54 +0000 (UTC) (envelope-from deischen@freebsd.org) Received: from sea.ntplx.net (sea.ntplx.net [204.213.176.11]) by mail.netplex.net (8.14.1/8.14.1/NETPLEX) with ESMTP id l9TLwWb5004025; Mon, 29 Oct 2007 17:58:32 -0400 (EDT) X-Virus-Scanned: by AMaViS and Clam AntiVirus (mail.netplex.net) X-Greylist: Message whitelisted by DRAC access database, not delayed by milter-greylist-3.0 (mail.netplex.net [204.213.176.10]); Mon, 29 Oct 2007 17:58:32 -0400 (EDT) Date: Mon, 29 Oct 2007 17:58:32 -0400 (EDT) From: Daniel Eischen X-X-Sender: eischen@sea.ntplx.net To: Kris Kennaway In-Reply-To: <4726560F.5050804@FreeBSD.org> Message-ID: References: <200710292101.l9TL1mAE049561@repoman.freebsd.org> <472650BF.5060706@FreeBSD.org> <4726560F.5050804@FreeBSD.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/lib/libthr/thread thr_mutex.c src/lib/libkse/thread thr_mutex.c src/include pthread.h X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Daniel Eischen List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Oct 2007 21:58:55 -0000 On Mon, 29 Oct 2007, Kris Kennaway wrote: > Daniel Eischen wrote: >> On Mon, 29 Oct 2007, Kris Kennaway wrote: >> >>> Daniel Eischen wrote: >>>> >>>> The libkse implementation already spins for a bit. The default >>>> number of spins is 500. >>> >>> OK, cool. >>> >>>> I'm not sure that another mutex type is warranted, the default >>>> mutex implementation should be adaptive I think. >>> >>> The point being that certain existing applications already know about this >>> mutex name and will use it automatically when it exists. >>> >>> I am a bit wary of making this the default type though. The algorithm is >>> a pessimization when the conditions described above are not true. >> >> I agree, and it applies a little to the KSE approach also. >> Spinning is mostly a hack for not being able to tell in >> userland if a thread is swapped in/out or is on another >> CPU. If you solve that problem, then you can make the >> default mutex adaptive. > > Yeah. It looks like Solaris does this. In principle you could do it cheaply > with a shared page, I'm not sure what Solaris does. I think we should add back the thread mailbox for libthr threads. I was in favor of keeping the mailbox for libthr, and this might be a good use for it. -- DE