From owner-svn-src-head@freebsd.org  Sat Feb 18 12:18:15 2017
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 068FCCE4DBE
 for <svn-src-head@mailman.ysv.freebsd.org>;
 Sat, 18 Feb 2017 12:18:15 +0000 (UTC)
 (envelope-from markmi@dsl-only.net)
Received: from asp.reflexion.net (outbound-mail-210-76.reflexion.net
 [208.70.210.76])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id AA9F417D0
 for <svn-src-head@freebsd.org>; Sat, 18 Feb 2017 12:18:14 +0000 (UTC)
 (envelope-from markmi@dsl-only.net)
Received: (qmail 18916 invoked from network); 18 Feb 2017 12:18:06 -0000
Received: from unknown (HELO mail-cs-01.app.dca.reflexion.local) (10.81.19.1)
 by 0 (rfx-qmail) with SMTP; 18 Feb 2017 12:18:06 -0000
Received: by mail-cs-01.app.dca.reflexion.local
 (Reflexion email security v8.30.0) with SMTP;
 Sat, 18 Feb 2017 07:18:06 -0500 (EST)
Received: (qmail 24895 invoked from network); 18 Feb 2017 12:18:06 -0000
Received: from unknown (HELO iron2.pdx.net) (69.64.224.71)
 by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 18 Feb 2017 12:18:06 -0000
Received: from [192.168.1.111] (c-67-170-167-181.hsd1.or.comcast.net
 [67.170.167.181])
 by iron2.pdx.net (Postfix) with ESMTPSA id E5578EC7EC3;
 Sat, 18 Feb 2017 04:18:05 -0800 (PST)
From: Mark Millard <markmi@dsl-only.net>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0 (Mac OS X Mail 10.2 \(3259\))
Subject: Re: svn commit: r313268 - head/sys/kern [through -r313271 for
 atomic_fcmpset use and later: fails on PowerMac G5 "Quad Core"; -r313266
 works]
Message-Id: <2FD12B8F-2255-470A-98D4-2DCE9C7495F5@dsl-only.net>
Date: Sat, 18 Feb 2017 04:18:05 -0800
Cc: Nathan Whitehorn <nwhitehorn@freebsd.org>
To: mjg@freebsd.org, Justin Hibbits <chmeeedalf@gmail.com>,
 svn-src-head@freebsd.org, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>,
 FreeBSD Current <freebsd-current@freebsd.org>
X-Mailer: Apple Mail (2.3259)
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.23
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 18 Feb 2017 12:18:15 -0000

[Note: I experiment with clang based powerpc64 builds,
reporting problems that I find. Justin is familiar
with this, as is Nathan.]

I tried to update the PowerMac G5 (a so-called "Quad Core")
that I have access to from head -r312761 to -r313864 and
ended up with random panics and hang ups in fairly short
order after booting.

Some approximate bisecting for the kernel lead to:
(sometimes getting part way into a buildkernel attempt
for a different version before a failure happens)

-r313266: works (just before use of atomic_fcmpset)
vs.
-r313271: fails (last of the "use atomic_fcmpset" check-ins)

(I did not try -r313268 through -r313270 as the use was
gradually added.)

So I'm currently running a -r313864 world with a -r313266
kernel.

No kernel that I tried that was from before -r313266 had the
problems.

Any kernel that I tried that was from after -r313271 had the
problems.

Of course I did not try them all in other direction. :)

===
Mark Millard
markmi at dsl-only.net