From owner-freebsd-hackers@FreeBSD.ORG  Sat Jan 28 13:22:17 2012
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 2B497106566C
	for <freebsd-hackers@freebsd.org>; Sat, 28 Jan 2012 13:22:17 +0000 (UTC)
	(envelope-from asmrookie@gmail.com)
Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50])
	by mx1.freebsd.org (Postfix) with ESMTP id 8ACF48FC12
	for <freebsd-hackers@freebsd.org>; Sat, 28 Jan 2012 13:22:16 +0000 (UTC)
Received: by wgbdr11 with SMTP id dr11so2846766wgb.31
	for <multiple recipients>; Sat, 28 Jan 2012 05:22:15 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma;
	h=mime-version:sender:in-reply-to:references:date
	:x-google-sender-auth:message-id:subject:from:to:cc:content-type
	:content-transfer-encoding;
	bh=R2Bl2pP8EvEKIHaRDJrUdTXEIbSIgeVjHxYRXxABTBM=;
	b=h7EdcPXmT240kuTFPF2xntbpOIRJZX8OVSYWb53mUr+1vhoKhXr+0iEkDSC3xnY7Sh
	cSxVI2gN/DGFSjVxCuEdeHGY+sSHPVP1svxZQeqbxI4hEVT4kOsJ7Cq8Xm9FDcAGTy50
	1lZ77JDuQJk1fXJ239d08YdMmi9TlWr7mcVaI=
MIME-Version: 1.0
Received: by 10.180.99.199 with SMTP id es7mr17097578wib.10.1327756935648;
	Sat, 28 Jan 2012 05:22:15 -0800 (PST)
Sender: asmrookie@gmail.com
Received: by 10.216.177.73 with HTTP; Sat, 28 Jan 2012 05:22:15 -0800 (PST)
In-Reply-To: <CAFMmRNyPkwx3hRtraq6QL64kibAeV3W23FE34T1oDnf9SVFOYg@mail.gmail.com>
References: <CAFMmRNxF1uMOr39BbZkpPN=uM7G09dtcckAYw8ag6n6bi=FeOw@mail.gmail.com>
	<CAJ-FndDHsQRRNmrS7fsELEVohozWvvfaZ6eW_GipwHdjU9ZwxA@mail.gmail.com>
	<CAFMmRNyPkwx3hRtraq6QL64kibAeV3W23FE34T1oDnf9SVFOYg@mail.gmail.com>
Date: Sat, 28 Jan 2012 14:22:15 +0100
X-Google-Sender-Auth: yWPJ0snojx1dlKOxD5AlGyVxc5E
Message-ID: <CAJ-FndD3366-uT191jMva3P-uL0DHi6nFeRfdsKA1hbJW7WqEA@mail.gmail.com>
From: Attilio Rao <attilio@freebsd.org>
To: Ryan Stone <rysto32@gmail.com>, Peter Holm <pho@freebsd.org>,
	Florian Smeets <flo@smeets.im>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Cc: freebsd-hackers@freebsd.org
Subject: Re: Kernel threads inherit CPU affinity from random sibling
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 28 Jan 2012 13:22:17 -0000

2012/1/28 Ryan Stone <rysto32@gmail.com>:
> On Fri, Jan 27, 2012 at 10:41 PM, Attilio Rao <attilio@freebsd.org> wrote=
:
>> I think what you found out is very sensitive.
>> However, the patch is not correct as you cannot call
>> cpuset_setthread() with thread_lock held.
>
> Whoops! =C2=A0I actually discovered that for myself and had already fixed
> it, but apparently I included an old version of the patch in the
> email.
>
>> Hence this is my fix:
>> http://www.freebsd.org/~attilio/cpuset_root.patch
>
> Oh, I do like this better. =C2=A0I tried something similar myself but
> abandoned it because I misread how sched_affinity() was implemented by
> 4BSD(I had gotten the impression that once TSF_AFFINITY is set it
> could never be cleared).

Do you have a pathological test-case for it? Are you going to test the patc=
h?

Thanks,
Attilio


--=20
Peace can only be achieved by understanding - A. Einstein