Am 08.08.2018 um 11:59 schrieb Huang Rui:
> I continue to work for bulk moving that based on the proposal by Christian.
>
> Background:
> amdgpu driver will move all PD/PT and PerVM BOs into idle list. Then move all of
> them on the end of LRU list one by one. Thus, that cause so many BOs moved to
> the end of the LRU, and impact performance seriously.
>
> Then Christian provided a workaround to not move PD/PT BOs on LRU with below
> patch:
> "drm/amdgpu: band aid validating VM PTs"
> Commit 0bbf32026cf5ba41e9922b30e26e1bed1ecd38ae
>
> However, the final solution should bulk move all PD/PT and PerVM BOs on the LRU
> instead of one by one.
>
> Whenever amdgpu_vm_validate_pt_bos() is called and we have BOs which need to be
> validated we move all BOs together to the end of the LRU without dropping the
> lock for the LRU.
>
> While doing so we note the beginning and end of this block in the LRU list.
>
> Now when amdgpu_vm_validate_pt_bos() is called and we don't have anything to do,
> we don't move every BO one by one, but instead cut the LRU list into pieces so
> that we bulk move everything to the end in just one operation.
>
> Test data:
> +--------------+-----------------+-----------+---------------------------------------+
> | |The Talos |Clpeak(OCL)|BusSpeedReadback(OCL) |
> | |Principle(Vulkan)| | |
> +------------------------------------------------------------------------------------+
> | | | |0.319 ms(1k) 0.314 ms(2K) 0.308 ms(4K) |
> | Original | 147.7 FPS | 76.86 us |0.307 ms(8K) 0.310 ms(16K) |
> +------------------------------------------------------------------------------------+
> | Orignial + WA| | |0.254 ms(1K) 0.241 ms(2K) |
> |(don't move | 162.1 FPS | 42.15 us |0.230 ms(4K) 0.223 ms(8K) 0.204 ms(16K)|
> |PT BOs on LRU)| | | |
> +------------------------------------------------------------------------------------+
> | Bulk move | 163.1 FPS | 40.52 us |0.244 ms(1K) 0.252 ms(2K) 0.213 ms(4K) |
> | | | |0.214 ms(8K) 0.225 ms(16K) |
> +--------------+-----------------+-----------+---------------------------------------+
>
> After test them with above three benchmarks include vulkan and opencl. We can
> see the visible improvement than original, and even better than original with
> workaround.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Huang Rui <ray.huang at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 22 ++++++++++++++--------
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 4 ++++
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 9c84770..eda0bb9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -286,6 +286,7 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> {
> struct ttm_bo_global *glob = adev->mman.bdev.glob;
> struct amdgpu_vm_bo_base *bo_base, *tmp;
> + bool validated = false;
> int r = 0;
>
> list_for_each_entry_safe(bo_base, tmp, &vm->evicted, vm_status) {
> @@ -295,14 +296,9 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> r = validate(param, bo);
> if (r)
> break;
> -
> - spin_lock(&glob->lru_lock);
> - ttm_bo_move_to_lru_tail(&bo->tbo, NULL);
> - if (bo->shadow)
> - ttm_bo_move_to_lru_tail(&bo->shadow->tbo, NULL);
> - spin_unlock(&glob->lru_lock);
> }
>
> + validated = true;
> if (bo->tbo.type != ttm_bo_type_kernel) {
> spin_lock(&vm->moved_lock);
> list_move(&bo_base->vm_status, &vm->moved);
> @@ -312,6 +308,15 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> }
> }
>
> + if (!validated) {
> + spin_lock(&glob->lru_lock);
> + ttm_bo_bulk_move_lru_tail(&vm->lru_bulk_move);
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
> +
> + memset(&vm->lru_bulk_move, 0, sizeof(vm->lru_bulk_move));
> +
> spin_lock(&glob->lru_lock);
> list_for_each_entry(bo_base, &vm->idle, vm_status) {
> struct amdgpu_bo *bo = bo_base->bo;
> @@ -319,9 +324,10 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> if (!bo->parent)
> continue;
>
> - ttm_bo_move_to_lru_tail(&bo->tbo, NULL);
> + ttm_bo_move_to_lru_tail(&bo->tbo, &vm->lru_bulk_move);
> if (bo->shadow)
> - ttm_bo_move_to_lru_tail(&bo->shadow->tbo, NULL);
> + ttm_bo_move_to_lru_tail(&bo->shadow->tbo,
> + &vm->lru_bulk_move);
Here is still one problem: The BOs currently evicted are not yet in the
idle state.
So this must be moved to the end of the state machine, probably best if
we put that into a separate function.
Regards,
Christian.
> }
> spin_unlock(&glob->lru_lock);
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index 67a15d4..92725ac 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -29,6 +29,7 @@
> #include <linux/rbtree.h>
> #include <drm/gpu_scheduler.h>
> #include <drm/drm_file.h>
> +#include <drm/ttm/ttm_bo_driver.h>
>
> #include "amdgpu_sync.h"
> #include "amdgpu_ring.h"
> @@ -226,6 +227,9 @@ struct amdgpu_vm {
>
> /* Some basic info about the task */
> struct amdgpu_task_info task_info;
> +
> + /* Store positions of group of BOs */
> + struct ttm_lru_bulk_move lru_bulk_move;
> };
>
> struct amdgpu_vm_manager {
