From owner-freebsd-threads@FreeBSD.ORG  Tue Aug  5 15:22:09 2003
Return-Path: <owner-freebsd-threads@FreeBSD.ORG>
Delivered-To: freebsd-threads@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 5CE2E37B401; Tue,  5 Aug 2003 15:22:09 -0700 (PDT)
Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id EEF4C43F3F; Tue,  5 Aug 2003 15:22:08 -0700 (PDT)
	(envelope-from davidxu@FreeBSD.org)
Received: from localhost (davidxu@localhost [127.0.0.1])
	by freefall.freebsd.org (8.12.9/8.12.9) with ESMTP id h75MM6Up085138;
	Tue, 5 Aug 2003 15:22:07 -0700 (PDT)
	(envelope-from davidxu@FreeBSD.org)
From: David Xu <davidxu@FreeBSD.org>
To: Julian Elischer <julian@elischer.org>,
	Marcel Moolenaar <marcel@xcllnt.net>
Date: Wed, 6 Aug 2003 06:25:09 +0800
User-Agent: KMail/1.5.2
References: <Pine.BSF.4.21.0308051013210.82100-100000@InterJet.elischer.org>
In-Reply-To: <Pine.BSF.4.21.0308051013210.82100-100000@InterJet.elischer.org>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200308060625.09817.davidxu@FreeBSD.org>
cc: threads@FreeBSD.org
Subject: Re: Good news: KSE on ia64 is starting to work
X-BeenThere: freebsd-threads@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
Reply-To: davidxu@FreeBSD.org
List-Id: Threading on FreeBSD <freebsd-threads.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-threads>,
	<mailto:freebsd-threads-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-threads>
List-Post: <mailto:freebsd-threads@freebsd.org>
List-Help: <mailto:freebsd-threads-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-threads>,
	<mailto:freebsd-threads-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 05 Aug 2003 22:22:09 -0000

On Wednesday 06 August 2003 01:22, Julian Elischer wrote:
> On Tue, 5 Aug 2003, Marcel Moolenaar wrote:
> > Ok,
> >
> > I have a couple of changes and fixes in my tree that makes KSE on
> > ia64 work. I have a couple of questions before I can commit it:
>
> On ia64 the TP will point to the TDB, as the spec says.
>
> there is only one case where this negatively impacts
> libKSE and that is where the thread is setting itself into a critical
> region.
>
> in i386 it is
>
> movl #0, %gs(offset)  (clear a value in the KCB)
>
> which can be done atomically
> since on ia64 TP points to teh THREAD structure,
> we have a second method of setting a critical region which is inthe TCB
> instead of being in the KCB, because
>
> using pdp11 syntax,
> offset(TCB)->reg
> NULL -> offset2(reg)
>
> cannot be done atomically and pre-emption may result in teh thread
> switching KSEs between teh two instructions.
> So on ia64 the critical region is defined as being enterred when
> the alternative flag in the TCB is used..
>
> David and Dan have more info and patches
>

I had committed a patch for kernel, the patch introduces a TMF_NOUPCALL
flag which can be used for ia64 and alpha in libkse. I think Dan can
commit his libkse patch now.


David Xu