Re: [PATCH 2/2] drm/amd/sched: add schuduling policy

[zhoucm1 <david1.zhou-5C7GfCeVMHo@public.gmane.org>]

On 2017年03月16日 17:10, Christian König wrote:
> Am 16.03.2017 um 10:00 schrieb Chunming Zhou:
>> if high priority rq is full, then process with low priority could be 
>> starve.
>> Add policy for this problem, the high proiority can ahead of next 
>> priority queue,
>> the ratio is 2 : 1.
>>
>> Change-Id: I58f4a6b9cdce8689b18dd8e83dd6e2cf5f99d5fb
>> Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
>
> Well, the idea behind the high priority queues is to actually starve 
> the low priority queues to a certain amount.
>
> At least for the kernel queue that is really desired.
Yes, agree, but we certainly don't want  low priority queue is totally 
dead, which doesn't have chance to run if high priority queue is always 
full and busy.
If without Andres changes, it doesn't matter. But after Andres changes 
upstream, we need scheduling policy.

Regards,
David Zhou
>
> Christian.
>
>> ---
>>   drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 26 
>> +++++++++++++++++++++++---
>>   drivers/gpu/drm/amd/scheduler/gpu_scheduler.h |  2 ++
>>   2 files changed, 25 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c 
>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>> index 0f439dd..4637b6f 100644
>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>> @@ -35,11 +35,16 @@
>>   static void amd_sched_process_job(struct fence *f, struct fence_cb 
>> *cb);
>>     /* Initialize a given run queue struct */
>> -static void amd_sched_rq_init(struct amd_sched_rq *rq)
>> +static void amd_sched_rq_init(struct amd_gpu_scheduler *sched, enum
>> +                  amd_sched_priority pri)
>>   {
>> +    struct amd_sched_rq *rq = &sched->sched_rq[pri];
>> +
>>       spin_lock_init(&rq->lock);
>>       INIT_LIST_HEAD(&rq->entities);
>>       rq->current_entity = NULL;
>> +    rq->wait_base = pri * 2;
>> +    rq->wait = rq->wait_base;
>>   }
>>     static void amd_sched_rq_add_entity(struct amd_sched_rq *rq,
>> @@ -494,17 +499,32 @@ static void amd_sched_wakeup(struct 
>> amd_gpu_scheduler *sched)
>>   {
>>       struct amd_sched_entity *entity;
>>       int i;
>> +    bool skip;
>>         if (!amd_sched_ready(sched))
>>           return NULL;
>>   +retry:
>> +    skip = false;
>>       /* Kernel run queue has higher priority than normal run queue*/
>>       for (i = AMD_SCHED_PRIORITY_MAX - 1; i >= 
>> AMD_SCHED_PRIORITY_MIN; i--) {
>> +        if ((i > AMD_SCHED_PRIORITY_MIN) &&
>> +            (sched->sched_rq[i - 1].wait >= 
>> sched->sched_rq[i].wait_base)) {
>> +            sched->sched_rq[i - 1].wait = sched->sched_rq[i - 
>> 1].wait_base;
>> +            skip = true;
>> +            continue;
>> +        }
>>           entity = amd_sched_rq_select_entity(&sched->sched_rq[i]);
>> -        if (entity)
>> +        if (entity) {
>> +            if (i > AMD_SCHED_PRIORITY_MIN)
>> +                sched->sched_rq[i - 1].wait++;
>>               break;
>> +        }
>>       }
>>   +    if (!entity && skip)
>> +        goto retry;
>> +
>>       return entity;
>>   }
>>   @@ -608,7 +628,7 @@ int amd_sched_init(struct amd_gpu_scheduler 
>> *sched,
>>       sched->name = name;
>>       sched->timeout = timeout;
>>       for (i = AMD_SCHED_PRIORITY_MIN; i < AMD_SCHED_PRIORITY_MAX; i++)
>> -        amd_sched_rq_init(&sched->sched_rq[i]);
>> +        amd_sched_rq_init(sched, i);
>>         init_waitqueue_head(&sched->wake_up_worker);
>>       init_waitqueue_head(&sched->job_scheduled);
>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h 
>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>> index 99f0240..4caed30 100644
>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>> @@ -64,6 +64,8 @@ struct amd_sched_rq {
>>       spinlock_t        lock;
>>       struct list_head    entities;
>>       struct amd_sched_entity    *current_entity;
>> +    int wait_base;
>> +    int wait;
>>   };
>>     struct amd_sched_fence {
>
>

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