Messages in this thread |  | | | Date | Wed, 05 Dec 2007 15:53:59 -0500 | | From | Jie Chen <> | | Subject | Re: Possible bug from kernel 2.6.22 and above | |
Peter Zijlstra wrote:
> On Wed, 2007-11-21 at 15:34 -0500, Jie Chen wrote:
>
>> It is clearly that the synchronization overhead increases as the number
>> of threads increases in the kernel 2.6.21. But the synchronization
>> overhead actually decreases as the number of threads increases in the
>> kernel 2.6.23.8 (We observed the same behavior on kernel 2.6.22 as
>> well). This certainly is not a correct behavior. The kernels are
>> configured with CONFIG_SMP, CONFIG_NUMA, CONFIG_SCHED_MC,
>> CONFIG_PREEMPT_NONE, CONFIG_DISCONTIGMEM set. The complete kernel
>> configuration file is in the attachment of this e-mail.
>>
>> From what we have read, there was a new scheduler (CFS) appeared from
>> 2.6.22. We are not sure whether the above behavior is caused by the new
>> scheduler.
>
> If I read this correctly, you say that: .22 is the first bad one right?
>
> The new scheduler (CFS) was introduced in .23, so it seems another
> change would be responsible for this.
>
>
>
Hi, Peter:
Yes. We did observe this in 2.6.22. Thank you.
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Jie Chen
Scientific Computing Group
Thomas Jefferson National Accelerator Facility
12000, Jefferson Ave.
Newport News, VA 23606
(757)269-5046 (office) (757)269-6248 (fax)
chen@jlab.org
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