From owner-cvs-all@FreeBSD.ORG Mon Oct 29 22:22:18 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 D5E1C16A469; Mon, 29 Oct 2007 22:22:18 +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 7C85313C4AC; Mon, 29 Oct 2007 22:22:18 +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 l9TMBT0i011531; Mon, 29 Oct 2007 18:11:29 -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 18:11:29 -0400 (EDT) Date: Mon, 29 Oct 2007 18:11:29 -0400 (EDT) From: Daniel Eischen X-X-Sender: eischen@sea.ntplx.net To: Kris Kennaway In-Reply-To: <4726597A.6000004@FreeBSD.org> Message-ID: References: <200710292101.l9TL1mAE049561@repoman.freebsd.org> <472650BF.5060706@FreeBSD.org> <4726560F.5050804@FreeBSD.org> <4726597A.6000004@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 22:22:18 -0000 On Mon, 29 Oct 2007, Kris Kennaway wrote: > Daniel Eischen wrote: >> 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. > > I am not familiar with that code, can you point me to the change that removed > it? This was when David revised libthr, so it never really had a mailbox. libkse has the mailbox, and I would have preferred keeping a similar interface for libthr (specifying it on thr_create(2)). You can look at how it works for KSE as an example. -- DE