From owner-freebsd-hackers@FreeBSD.ORG  Fri Feb 14 19:18:31 2014
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 5809B5DE;
 Fri, 14 Feb 2014 19:18:31 +0000 (UTC)
Received: from mail-qc0-x235.google.com (mail-qc0-x235.google.com
 [IPv6:2607:f8b0:400d:c01::235])
 (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits))
 (No client certificate requested)
 by mx1.freebsd.org (Postfix) with ESMTPS id E3E271BF4;
 Fri, 14 Feb 2014 19:18:30 +0000 (UTC)
Received: by mail-qc0-f181.google.com with SMTP id e9so20437027qcy.26
 for <multiple recipients>; Fri, 14 Feb 2014 11:18:30 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
 h=mime-version:sender:in-reply-to:references:date:message-id:subject
 :from:to:cc:content-type;
 bh=jsS5cQgxKWF0vUwePrX33qb3N38GlytJ045P/Pc/MyM=;
 b=ZrVoWZAu+Zzsd450YJPyL8vJShIYYS3yNeIHfPHDBcFk+GNQ89Es9lG5k2t1ek0+I3
 un/88l3ydkG2Z+Z6gMq4mvzed9ZFgCyRGD/OoWg0/9Rwtz4JlWv6/3DH7id9CwEqtqwp
 M/wGlljgaBCERAfGWLGIKcHqBx4i/4rYBDpwrd9xigN6gHJDX5Fp5GHJGGd1xKz3opdP
 iCLuTwXFlQ/DBDrVswPcUWoc2qZmkmBHYazuRydLkgM94V43d0b5wYyeki/y8qTiKhfW
 sD3XefnghiAgVa+kvAAu4OcH34m0k12NIyKqhdQ627x/1AxWJIX77S1iySretoCiYX2c
 vWhw==
MIME-Version: 1.0
X-Received: by 10.229.179.5 with SMTP id bo5mr16190937qcb.21.1392405510104;
 Fri, 14 Feb 2014 11:18:30 -0800 (PST)
Sender: adrian.chadd@gmail.com
Received: by 10.224.16.10 with HTTP; Fri, 14 Feb 2014 11:18:30 -0800 (PST)
In-Reply-To: <201402141318.44743.jhb@freebsd.org>
References: <CAJ-Vmo=7Nz1jqXy+rTQ7u9_ZP7jeFOKUJxU1O51tYJjvTUmWTg@mail.gmail.com>
 <201402141139.49158.jhb@freebsd.org>
 <CAJ-Vmo=vQ+MX+r3z6_Y4aJiWUBxXgXE7APjTsUysVPN2aoghXQ@mail.gmail.com>
 <201402141318.44743.jhb@freebsd.org>
Date: Fri, 14 Feb 2014 11:18:30 -0800
X-Google-Sender-Auth: QEybOPM7Tbhp6qOcVV4ns4tncyg
Message-ID: <CAJ-Vmo=C4MRdyAGegD8MkCgx9ibbWtrWefYYugz=qpyOEmZcxg@mail.gmail.com>
Subject: Re: can the scheduler decide to schedule an interrupted but runnable
 thread on another CPU core? What are the implications for code?
From: Adrian Chadd <adrian@freebsd.org>
To: John Baldwin <jhb@freebsd.org>
Content-Type: text/plain; charset=ISO-8859-1
Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>,
 Ryan Stone <rysto32@gmail.com>,
 "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/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: Fri, 14 Feb 2014 19:18:31 -0000

On 14 February 2014 10:18, John Baldwin <jhb@freebsd.org> wrote:

> If they are all cpuset to a single CPU, they should not migrate, though
> I think sched_bind() can override that.  However, that requires code to
> explicitly call sched_bind() which should be rare.

Yup. That's why I'm confused.

I'm rebuilding -HEAD now with the latest flowtable changes. I'll add
in my debugging afterward and trigger the particular scenario where
it's behaving badly and do some more diagnostics.

Thanks,


-a