[PATCH 04/14] drm/amdkfd: Fix oversubscription accounting

[Oded Gabbay]

On Tue, Dec 5, 2017 at 9:27 PM, Felix Kuehling <felix.kuehling at amd.com> wrote:
> On 2017-12-05 03:10 AM, Oded Gabbay wrote:
>> On Tue, Nov 28, 2017 at 1:29 AM, Felix Kuehling <Felix.Kuehling at amd.com> wrote:
>>> Don't count SDMA queues towards compute HQD oversubscription when
>>> deciding whether to create a chained runlist.
>>>
>>> Signed-off-by: Jay Cornwall <Jay.Cornwall at amd.com>
>>> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
>>> ---
>>>  drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c | 5 +++--
>>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
>>> index 0b7092e..c3230b9 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
>>> @@ -55,13 +55,14 @@ static void pm_calc_rlib_size(struct packet_manager *pm,
>>>                                 unsigned int *rlib_size,
>>>                                 bool *over_subscription)
>>>  {
>>> -       unsigned int process_count, queue_count;
>>> +       unsigned int process_count, queue_count, compute_queue_count;
>>>         unsigned int map_queue_size;
>>>         unsigned int max_proc_per_quantum = 1;
>>>         struct kfd_dev *dev = pm->dqm->dev;
>>>
>>>         process_count = pm->dqm->processes_count;
>>>         queue_count = pm->dqm->queue_count;
>>> +       compute_queue_count = queue_count - pm->dqm->sdma_queue_count;
>>>
>>>         /* check if there is over subscription
>>>          * Note: the arbitration between the number of VMIDs and
>>> @@ -74,7 +75,7 @@ static void pm_calc_rlib_size(struct packet_manager *pm,
>>>                 max_proc_per_quantum = dev->max_proc_per_quantum;
>>>
>>>         if ((process_count > max_proc_per_quantum) ||
>>> -           queue_count > get_queues_num(pm->dqm)) {
>>> +           compute_queue_count > get_queues_num(pm->dqm)) {
>>>                 *over_subscription = true;
>>>                 pr_debug("Over subscribed runlist\n");
>>>         }
>>> --
>>> 2.7.4
>>>
>> Don't you need to update this line as well (I'm less familiar with the
>> runlist so just asking) ?
>>
>> *rlib_size = process_count * sizeof(struct pm4_mes_map_process) +
>> queue_count * map_queue_size;
>
> No. This change doesn't directly affect the runlist size. It deals with
> HW resource limitations and whether the HWS needs to handle compute
> queue oversubscription. SDMA queues don't count against the limited
> number of HQDs for compute queues. So we should not count them for
> determining compute queue oversubscription. But the SDMA queues are
> still part of the runlist IB, so rlib_size doesn't change.
>
> rlib_size will be indirectly affected, because just below this code
> modifies the runlist size for the oversubscription case:
>
>         /*
>          * Increase the allocation size in case we need a chained run list
>          * when over subscription
>          */
>         if (*over_subscription)
>                 *rlib_size += sizeof(struct pm4_mes_runlist);
>
> Regards,
>   Felix
>
>>
>> Oded
>
ok, thanks for the explanation.


This patch is:
Acked-by: Oded Gabbay <oded.gabbay at gmail.com>