From owner-freebsd-arch@FreeBSD.ORG  Wed Jun  6 19:03:44 2012
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: freebsd-arch@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 3B7FA106564A;
	Wed,  6 Jun 2012 19:03:44 +0000 (UTC)
	(envelope-from iwasaki@jp.FreeBSD.org)
Received: from locore.org (ns01.locore.org [218.45.21.227])
	by mx1.freebsd.org (Postfix) with ESMTP id DCF5F8FC0A;
	Wed,  6 Jun 2012 19:03:43 +0000 (UTC)
Received: from localhost (celeron.v4.locore.org [192.168.0.10])
	by locore.org (8.14.5/8.14.5/iwasaki) with ESMTP/inet id q56J3gH9050606;
	Thu, 7 Jun 2012 04:03:42 +0900 (JST)
	(envelope-from iwasaki@jp.FreeBSD.org)
Date: Thu, 07 Jun 2012 04:03:42 +0900 (JST)
Message-Id: <20120607.040342.73368798.iwasaki@jp.FreeBSD.org>
To: avg@FreeBSD.org
From: Mitsuru IWASAKI <iwasaki@jp.FreeBSD.org>
In-Reply-To: <4FCBBEDD.5000604@FreeBSD.org>
References: <4FCB0FE5.4050607@FreeBSD.org>
	<20120603.234243.28389486.iwasaki@jp.FreeBSD.org>
	<4FCBBEDD.5000604@FreeBSD.org>
X-Mailer: Mew version 3.3 on Emacs 20.7 / Mule 4.0 (HANANOEN)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: attilio@FreeBSD.org, freebsd-acpi@FreeBSD.org, freebsd-arch@FreeBSD.org
Subject: Re: cpu stopping
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 06 Jun 2012 19:03:44 -0000

Hi,

I've created the patches of experimental implementation based on
discussion so far.

http://people.freebsd.org/~iwasaki/acpi/cpustop_hook-20120606.diff

In acpi_wakeup.c, cpususpend_handler() and susppcbs are replaced with
cpustop_handler() and stoppcbs.

This is for RELENG_9 and only for i386 but I think it's enough for the
start.


From: Andriy Gapon <avg@FreeBSD.org>
Subject: Re: cpu stopping
Date: Sun, 03 Jun 2012 22:45:33 +0300
Message-ID: <4FCBBEDD.5000604@FreeBSD.org>

> > Never mind :) What I'm trying to do in the patches is just to unify
> > amd64/i386 independent part (acpi_wakeup.c) for the code maintenance,
> > so please let's commit it first, then start re-design the
> > cpususpend_handler().
> 
> In no way I am trying to delay your work :)
> Just shared my view on the design of cpu stopping code.

I got it :)

> >> My view of how this should work is:
> >> - there can be only one master CPU that controls all other (slave) CPUs
> >> - the master sets entry and exit hooks
> > 
> > Entry hook for suspending might be
> > ----
> >                 ctx_fpusave(suspfpusave[cpu]);
> >                 wbinvd();
> >                 CPU_SET_ATOMIC(cpu, &stopped_cpus);
> > ----
> > 
> > and for stopping is
> > ----
> >         /* Indicate that we are stopped */
> >         CPU_SET_ATOMIC(cpu, &stopped_cpus);
> > ----
> > 
> > Correct?
> 
> Yes.  The only nit is that CPU_SET_ATOMIC(cpu, &stopped_cpus) could be part of
> the wait loop prologue.  No need to duplicate it in each hook.

OK, I did so.

I hope the patch is not far from your idea.

Thanks!