Re: [RFC 1/6] Optimize wake-up task for Task Packing heuristic

[Dietmar Eggemann <dietmar.eggemann@arm.com>]

On 4/10/19 6:33 PM, Dietmar Eggemann wrote:
> On 4/7/19 7:57 AM, Parth Shah wrote:
>>
>>
>> On 3/27/19 3:01 PM, Dietmar Eggemann wrote:
>>> Hi Parth,
>>>
>>> On 3/22/19 7:06 AM, Parth Shah wrote:
> 
> [...]
> 
>>>> +    for_each_cpu_wrap(core, cpus, prev_cpu)
>>>> +    {
>>>> +        long unsigned int core_util = 0;
>>>> +        long unsigned int core_cap = core_cap_mf*capacity_of(core)/10;
>>>> +        long unsigned int cache_cpu_util = (unsigned)-1;
>>>> +        long unsigned est_util = 0, est_util_enqueued = 0;
>>>> +        int cache_cpu = core;
>>>> +        struct cfs_rq *cfs_rq;
>>>> +
>>>> +        for_each_cpu(smt, cpu_smt_mask(core)) {
>>>
>>> This one doesn't build for me on arm64 (make defconfig) since it uses 
>>> cpu_smt_mask() outside the CONFIG_SCHED_SMT guard.
>>>
>>> kernel/sched/fair.c: In function ‘select_non_idle_core’:
>>> kernel/sched/fair.c:6243:21: error: implicit declaration of function 
>>> ‘cpu_smt_mask’; did you mean ‘cpu_cpu_mask’? 
>>> [-Werror=implicit-function-declaration]
>>>     for_each_cpu(smt, cpu_smt_mask(core)) {
>>>                       ^
>>> ./include/linux/cpumask.h:242:32: note: in definition of macro 
>>> ‘for_each_cpu’
>>>
>>> [...]
>>>
>>
>> Thanks for pointing out. It will not build for individual patches for 
>> the current version of RFC.
>>
>> Please try to build it with full patch set. I assure, the following 
>> iterations of RFC will resolve this issue.
> 
> Ah, I see, you have this CONFIG_TURBO_SCHED patch at the end of the 
> series. I think that you will have a hard time to get new CONFIG 
> switches into the task scheduler code. Can you not bting in your feature 
> w/o CONFIG_TURBO_SCHED?

I think you could replace CONFIG_TURBO_SCHED entirely with your static 
key __turbo_sched_enabled (and the existing CONFIG_SMT in case your 
feature relies on SMT).

Please sent your next version to linux-kernel@vger.kernel.org as well 
and cc the task scheduler maintainer to get more review.