linux-kernel - Re: [PATCH 2/2] sched/deadline: don't need to balance during wakeup if wakee is pinned

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Message-ID: <544662CD.5070501@arm.com>
Date:	Tue, 21 Oct 2014 14:42:37 +0100
From:	Juri Lelli <juri.lelli@....com>
To:	Wanpeng Li <kernellwp@...il.com>,
	Wanpeng Li <wanpeng.li@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] sched/deadline: don't need to balance during wakeup
 if wakee is pinned

On 21/10/14 14:39, Wanpeng Li wrote:
> Hi Juri,
> 
> 于 10/21/14, 9:29 PM, Juri Lelli 写道:
>> Hi,
>>
>> On 21/10/14 13:19, Wanpeng Li wrote:
>>> Cc Juri,
>>>
>>> 于 10/14/14, 10:22 AM, Wanpeng Li 写道:
>>>> Use nr_cpus_allowed to bail from select_task_rq() when only one cpu
>>>> can be used, and saves some cycles for pinned tasks.
>>>>
>>>> Signed-off-by: Wanpeng Li <wanpeng.li@...ux.intel.com>
>>>> ---
>>>>   kernel/sched/deadline.c | 3 +++
>>>>   1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>>>> index f46b7f1..5874bf8 100644
>>>> --- a/kernel/sched/deadline.c
>>>> +++ b/kernel/sched/deadline.c
>>>> @@ -914,6 +914,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
>>>>   	struct task_struct *curr;
>>>>   	struct rq *rq;
>>>>   
>>>> +	if (p->nr_cpus_allowed == 1)
>>>> +		goto out;
>>>> +
>>>>   	if (sd_flag != SD_BALANCE_WAKE)
>>>>   		goto out;
>>>>
>> Apart from the encoding of the resend, it looks good, thanks!
> 
> What's your meaning of resend? Do you mean this one?

Nope. I just meant that I received your "Cc Juri" encoded as Chinese
Simplified. But, I guess the original lkml patch looks good. Sorry for
the confusion :).

Best,

- Juri

> 
> https://lkml.org/lkml/2014/10/10/425
> 
> I'm afraid they are different patches.
> 
> Regards,
> Wanpeng Li
> 
>>
>> Best,
>>
>> - Juri
>>
> 
> 

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