Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 3 Mar 2017 01:38:13 -0800
From:      Mark Millard <markmi@dsl-only.net>
To:        sgk@troutmask.apl.washington.edu, Mateusz Guzik <mjguzik@gmail.com>
Cc:        svn-src-head@freebsd.org, FreeBSD Current <freebsd-current@freebsd.org>, Justin Hibbits <chmeeedalf@gmail.com>, mjg@freebsd.org, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>
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:  <8D803761-644A-4E72-928F-2E96525A1A11@dsl-only.net>
In-Reply-To: <20170302151959.GA58624@troutmask.apl.washington.edu>
References:  <20170225002300.GC19697@dft-labs.eu> <12339EDD-5663-40E0-8553-821EF9B6CDEB@dsl-only.net> <EB9DBDFA-BAE9-4BFF-8E8B-BF7698362A11@dsl-only.net> <477BA631-AB85-4E77-8BA3-CD2AFAD5E405@dsl-only.net> <B38C6E4C-DC41-44A6-A99B-CD6FA5CB105C@dsl-only.net> <9A63B36E-5F81-4ECD-A2A2-AB442AAC26A6@dsl-only.net> <20170225193103.GA4379@dft-labs.eu> <20170301061350.GA22378@dft-labs.eu> <A949940F-DA18-4179-8C4F-956BE895E0EA@dsl-only.net> <20170302121021.GA32682@dft-labs.eu> <20170302151959.GA58624@troutmask.apl.washington.edu>

next in thread | previous in thread | raw e-mail | index | archive | help
On 2017-Mar-2, at 7:19 AM, Steve Kargl <sgk at =
troutmask.apl.washington.edu> wrote:

On Thu, Mar 02, 2017 at 01:10:21PM +0100, Mateusz Guzik wrote:
> On Wed, Mar 01, 2017 at 09:45:07AM -0800, Mark Millard wrote:
>>=20
>>> Summary of the transition interval:
>>>=20
>>> So for powerpc64 (and powerpc?) It is a good
>>> idea to avoid anything that is after -r313254
>>> and before -r314474 in head. (Would this be
>>> appropriate for a UPDATING notice given its
>>> span?)
>>>=20
>>> There may be other architectures that might have
>>> a similar status(?): the last fixes involved were
>>> not in Machine Dependent code. (Some architectures
>>> are apparently insensitive to the errors, such as
>>> amd64).
>>>=20
>>=20
>> When following current you are expected to be on the newest revision,
>> so I don't think mentioning interim broken releases makes much sense.
>>=20
>=20
> Documenting the range may aid those bisecting src/ to find a bug.=20
> How is one to know that anything in the range that Mark points
> out should be skipped on powerpc64?
>=20
> --=20
> Steve

I have tested with a TARGET_ARCH=3Dpowerpc -r314473 build and
its kernel version has locking problems like
TARGET_ARCH=3Dpowerpc64 does for that version.

[Note: This was run on a PowerMac G5 so-called "Quad Core"
so most of the memory was ignored.]

Both TARGET_ARCH=3Dpowerpc64 and TARGET_ARCH=3Dpowerpc need -r314474
or later as of the new locking.

I've not explicitly tested other architectures. As I remember
armv6/v7 are classified as having some from of a weak memory
model compared to the likes of amd64. If so armv6/v7 might be
candidates for having problems. There might be other candidates.


=3D=3D=3D
Mark Millard
markmi at dsl-only.net




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?8D803761-644A-4E72-928F-2E96525A1A11>