[PATCH v3 4/5] drm/amdgpu: use bulk moves for efficient VM LRU handling (v3)
Zhang, Jerry (Junwei)
Jerry.Zhang at amd.com
Tue Aug 14 02:26:43 UTC 2018
On 08/13/2018 05:58 PM, Huang Rui wrote:
> 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.
>
> v2: move all BOs include idle, relocated, and moved list to the end of LRU and
> put them together.
> v3: remove unused parameter and use list_for_each_entry instead of the one with
> save entry.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Huang Rui <ray.huang at amd.com>
> Tested-by: Mike Lothian <mike at fireburn.co.uk>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 73 ++++++++++++++++++++++++++--------
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 4 ++
> 2 files changed, 61 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 9c84770..ee1af53 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -268,6 +268,53 @@ void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
> }
>
> /**
> + * amdgpu_vm_move_to_lru_tail - move one list of BOs to end of LRU
> + *
> + * @vm: vm providing the BOs
> + * @list: the list that stored BOs
> + *
> + * Move one list of BOs to the end of LRU and update the positions.
> + */
> +static void
> +amdgpu_vm_move_to_lru_tail_by_list(struct amdgpu_vm *vm, struct list_head *list)
> +{
> + struct amdgpu_vm_bo_base *bo_base;
> +
> + list_for_each_entry(bo_base, list, vm_status) {
> + struct amdgpu_bo *bo = bo_base->bo;
> +
> + if (!bo->parent)
> + continue;
> +
> + ttm_bo_move_to_lru_tail(&bo->tbo, &vm->lru_bulk_move);
> + if (bo->shadow)
> + ttm_bo_move_to_lru_tail(&bo->shadow->tbo,
> + &vm->lru_bulk_move);
> + }
> +}
> +
> +/**
> + * amdgpu_vm_move_to_lru_tail - move all BOs to the end of LRU
> + *
> + * @adev: amdgpu device pointer
> + * @vm: vm providing the BOs
> + *
> + * Move all BOs to the end of LRU and remember their positions to put them
> + * together.
> + */
> +static void
> +amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev, struct amdgpu_vm *vm)
> +{
> + struct ttm_bo_global *glob = adev->mman.bdev.glob;
> +
> + spin_lock(&glob->lru_lock);
> + amdgpu_vm_move_to_lru_tail_by_list(vm, &vm->idle);
> + amdgpu_vm_move_to_lru_tail_by_list(vm, &vm->relocated);
> + amdgpu_vm_move_to_lru_tail_by_list(vm, &vm->moved);
Moved list is working under vm->moved_lock, so we may hold that as well.
otherwise, to use the same one.
(not sure the detail of history about moved_lock)
> + spin_unlock(&glob->lru_lock);
> +}
> +
> +/**
> * amdgpu_vm_validate_pt_bos - validate the page table BOs
> *
> * @adev: amdgpu device pointer
> @@ -286,6 +333,7 @@ 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 +343,9 @@ 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);
> @@ -312,18 +355,16 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
> }
> }
>
> - spin_lock(&glob->lru_lock);
> - list_for_each_entry(bo_base, &vm->idle, vm_status) {
> - struct amdgpu_bo *bo = bo_base->bo;
> + if (!validated) {
> + spin_lock(&glob->lru_lock);
> + ttm_bo_bulk_move_lru_tail(&vm->lru_bulk_move);
To confirm
we only do actual bulk move when no evicted or validate failure?
Regards,
Jerry
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
>
> - if (!bo->parent)
> - continue;
> + memset(&vm->lru_bulk_move, 0, sizeof(vm->lru_bulk_move));
>
> - 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);
> + amdgpu_vm_move_to_lru_tail(adev, vm);
>
> return r;
> }
> 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 {
>
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