Re: [tip:core/rcu] Revert "rcu: Decrease memory-barrier usage based on semi-formal proof"

[Yinghai Lu <yinghai@kernel.org>]

On 05/23/2011 03:01 PM, Yinghai Lu wrote:
> On 05/23/2011 02:25 PM, Paul E. McKenney wrote:
>> On Mon, May 23, 2011 at 01:14:22PM -0700, Yinghai Lu wrote:
>>> On 05/21/2011 07:08 AM, Paul E. McKenney wrote:
>>>> On Sat, May 21, 2011 at 06:18:44AM -0700, Paul E. McKenney wrote:
>>>>> On Fri, May 20, 2011 at 05:02:40PM -0700, Yinghai Lu wrote:
>>>>>> On 05/20/2011 04:49 PM, Paul E. McKenney wrote:
>>>>>>> On Fri, May 20, 2011 at 04:16:28PM -0700, Yinghai Lu wrote:
>>>>>> ...
>>>>>>>>
>>>>>>>> the same one i sent out before, but let DEBUG_LOCKING_API_SELFTESTS disabled.
>>>>>>>
>>>>>>> OK, just to make sure I understand...  You are compiling exactly the
>>>>>>> same kernel source tree with exactly the same .config, just with two
>>>>>>> different versions of gcc, correct?
>>>>>> yes.
>>>>>>>
>>>>>>> If so, it is quite possible that the slow one is the correct one.  :-/
>>>>>> yeah, new version always have problem.
>>>>>>
>>>>>> looks like opensuse11.3 has 4.5.0 and fedora14 has 4.5.1
>>>>>
>>>>> OK, so fedora14 is the fast one (4.5.1) and opensuse11.3 is the slow
>>>>> one (4.5.0), correct?
>>>>
>>>> And does commit c7a3786030 help?  This commit (from Peter Zijlstra)
>>>> tidied up RCU kthreads' scheduler interactions.  The patch is below,
>>>> though it is probably more convenient to pull it from the rcu/next
>>>> branch of:
>>>>
>>>>   git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
>>>>
>>
gcc in Fedora 14 is fine with your tree.

Looks like I need to dump openuse 11.3 now.

Thanks

Yinghai