Re: [PATCH 1/2] drm/amdgpu: group BOs by log2 of the size on the LRU

["Christian König" <deathsimple@vodafone.de>]

Am 14.04.2016 um 16:23 schrieb Alex Deucher:
> On Thu, Apr 14, 2016 at 8:54 AM, Christian König
> <deathsimple@vodafone.de> wrote:
>> From: Christian König <christian.koenig@amd.com>
>>
>> This allows us to have small BOs on the LRU before big ones.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
> Have you done any benchmarking to see how much this helps when there
> is memory contention?

Still working on this. Marek could you help with that? You usually have 
the Unigin benchmarks ready at hand.

Christian.

>
> For the series:
> Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h     | 11 ++++++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 59 +++++++++++++++++++++++++++++++--
>>   2 files changed, 68 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index c4a21c6..7b90323 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -391,6 +391,14 @@ unsigned amdgpu_fence_count_emitted(struct amdgpu_ring *ring);
>>   /*
>>    * TTM.
>>    */
>> +
>> +#define AMDGPU_TTM_LRU_SIZE    20
>> +
>> +struct amdgpu_mman_lru {
>> +       struct list_head                *lru[TTM_NUM_MEM_TYPES];
>> +       struct list_head                *swap_lru;
>> +};
>> +
>>   struct amdgpu_mman {
>>          struct ttm_bo_global_ref        bo_global_ref;
>>          struct drm_global_reference     mem_global_ref;
>> @@ -408,6 +416,9 @@ struct amdgpu_mman {
>>          struct amdgpu_ring                      *buffer_funcs_ring;
>>          /* Scheduler entity for buffer moves */
>>          struct amd_sched_entity                 entity;
>> +
>> +       /* custom LRU management */
>> +       struct amdgpu_mman_lru                  log2_size[AMDGPU_TTM_LRU_SIZE];
>>   };
>>
>>   int amdgpu_copy_buffer(struct amdgpu_ring *ring,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index fefaa9b..b58a445 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -910,6 +910,50 @@ uint32_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
>>          return flags;
>>   }
>>
>> +static void amdgpu_ttm_lru_removal(struct ttm_buffer_object *tbo)
>> +{
>> +       struct amdgpu_device *adev = amdgpu_get_adev(tbo->bdev);
>> +       unsigned i;
>> +
>> +       for (i = 0; i < AMDGPU_TTM_LRU_SIZE; ++i) {
>> +               struct amdgpu_mman_lru *lru = &adev->mman.log2_size[i];
>> +
>> +               if (&tbo->lru == lru->lru[tbo->mem.mem_type])
>> +                       lru->lru[tbo->mem.mem_type] = tbo->lru.prev;
>> +
>> +               if (&tbo->swap == lru->swap_lru)
>> +                       lru->swap_lru = tbo->swap.prev;
>> +       }
>> +}
>> +
>> +static struct amdgpu_mman_lru *amdgpu_ttm_lru(struct ttm_buffer_object *tbo)
>> +{
>> +       struct amdgpu_device *adev = amdgpu_get_adev(tbo->bdev);
>> +       unsigned log2_size = min(ilog2(tbo->num_pages), AMDGPU_TTM_LRU_SIZE);
>> +
>> +       return &adev->mman.log2_size[log2_size];
>> +}
>> +
>> +static struct list_head *amdgpu_ttm_lru_tail(struct ttm_buffer_object *tbo)
>> +{
>> +       struct amdgpu_mman_lru *lru = amdgpu_ttm_lru(tbo);
>> +       struct list_head *res = lru->lru[tbo->mem.mem_type];
>> +
>> +       lru->lru[tbo->mem.mem_type] = &tbo->lru;
>> +
>> +       return res;
>> +}
>> +
>> +static struct list_head *amdgpu_ttm_swap_lru_tail(struct ttm_buffer_object *tbo)
>> +{
>> +       struct amdgpu_mman_lru *lru = amdgpu_ttm_lru(tbo);
>> +       struct list_head *res = lru->swap_lru;
>> +
>> +       lru->swap_lru = &tbo->swap;
>> +
>> +       return res;
>> +}
>> +
>>   static struct ttm_bo_driver amdgpu_bo_driver = {
>>          .ttm_tt_create = &amdgpu_ttm_tt_create,
>>          .ttm_tt_populate = &amdgpu_ttm_tt_populate,
>> @@ -923,12 +967,14 @@ static struct ttm_bo_driver amdgpu_bo_driver = {
>>          .fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
>>          .io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
>>          .io_mem_free = &amdgpu_ttm_io_mem_free,
>> -       .lru_tail = &ttm_bo_default_lru_tail,
>> -       .swap_lru_tail = &ttm_bo_default_swap_lru_tail,
>> +       .lru_removal = &amdgpu_ttm_lru_removal,
>> +       .lru_tail = &amdgpu_ttm_lru_tail,
>> +       .swap_lru_tail = &amdgpu_ttm_swap_lru_tail,
>>   };
>>
>>   int amdgpu_ttm_init(struct amdgpu_device *adev)
>>   {
>> +       unsigned i, j;
>>          int r;
>>
>>          r = amdgpu_ttm_global_init(adev);
>> @@ -946,6 +992,15 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>>                  DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
>>                  return r;
>>          }
>> +
>> +       for (i = 0; i < AMDGPU_TTM_LRU_SIZE; ++i) {
>> +               struct amdgpu_mman_lru *lru = &adev->mman.log2_size[i];
>> +
>> +               for (j = 0; j < TTM_NUM_MEM_TYPES; ++j)
>> +                       lru->lru[j] = &adev->mman.bdev.man[j].lru;
>> +               lru->swap_lru = &adev->mman.bdev.glob->swap_lru;
>> +       }
>> +
>>          adev->mman.initialized = true;
>>          r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_VRAM,
>>                                  adev->mc.real_vram_size >> PAGE_SHIFT);
>> --
>> 2.5.0
>>

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