[PATCH v4 4/5] drm/amdgpu: use bulk moves for efficient VM LRU handling (v4)
Christian König
ckoenig.leichtzumerken at gmail.com
Mon Aug 20 13:17:12 UTC 2018
Am 20.08.2018 um 08:05 schrieb Huang Rui:
> On Fri, Aug 17, 2018 at 06:38:16PM +0800, Koenig, Christian wrote:
>> Am 17.08.2018 um 12:08 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.
>>>
>>> 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.
>>> v4: move the amdgpu_vm_move_to_lru_tail after command submission, at that time,
>>> all bo will be back on idle list.
>>>
>>> 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>
>>> Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de>
>>> Acked-by: Chunming Zhou <david1.zhou at amd.com>
>>> ---
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 11 ++++++
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 71 ++++++++++++++++++++++++++--------
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 11 +++++-
>>> 3 files changed, 75 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> index 502b94f..9fbdf02 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>> @@ -1260,6 +1260,16 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>>> return 0;
>>> }
>>>
>>> +static void amdgpu_cs_vm_move_on_lru(struct amdgpu_device *adev,
>>> + struct amdgpu_cs_parser *p)
>>> +{
>>> + struct amdgpu_fpriv *fpriv = p->filp->driver_priv;
>>> + struct amdgpu_vm *vm = &fpriv->vm;
>>> +
>>> + if (vm->validated)
>> That check belongs inside amdgpu_vm_move_to_lru_tail().
>>
>>> + amdgpu_vm_move_to_lru_tail(adev, vm);
>>> +}
>>> +
>>> int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>>> {
>>> struct amdgpu_device *adev = dev->dev_private;
>>> @@ -1310,6 +1320,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>>>
>>> r = amdgpu_cs_submit(&parser, cs);
>>>
>>> + amdgpu_cs_vm_move_on_lru(adev, &parser);
>>> out:
>>> amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
>>> return r;
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> index 9c84770..037cfbc 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_by_list - 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)
>> I don't see much of a point having a separate function for this any more.
>>
>>> +{
>>> + 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.
>>> + */
>>> +void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
>>> + struct amdgpu_vm *vm)
>>> +{
>>> + struct ttm_bo_global *glob = adev->mman.bdev.glob;
>>> +
>>> + memset(&vm->lru_bulk_move, 0, sizeof(vm->lru_bulk_move));
>>> +
>>> + spin_lock(&glob->lru_lock);
>>> + amdgpu_vm_move_to_lru_tail_by_list(vm, &vm->idle);
>>> + spin_unlock(&glob->lru_lock);
>>> +}
>>> +
>>> +/**
>>> * amdgpu_vm_validate_pt_bos - validate the page table BOs
>>> *
>>> * @adev: amdgpu device pointer
>>> @@ -288,6 +335,7 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>> struct amdgpu_vm_bo_base *bo_base, *tmp;
>>> int r = 0;
>>>
>>> + vm->validated = false;
>> That won't work like this. It is perfectly possible that CS is aborted
>> because of a signal and amdgpu_vm_move_to_lru_tail() never called.
>>
>> I suggest to do "vm->validated |= !list_empty(&vm->evicted);" here and
>> then set it to false again in amdgpu_vm_move_to_lru_tail().
>>
>> And maybe we need a better name than "validated", maybe "bulk_moveable"
>> or something like that.
>>
> Actually, "validated" is opposite to "bulk_moveable".
> So how about use "vm->bulk_moveable = list_empty(&vm->evicted);" here
That still won't work correct. See the validation can be interrupted.
So we need something like "vm->bulk_moveable &=
list_empty(&vm->evicted);" here.
Apart from that this now looks really good to me.
Regards,
Christian.
>
> Then check the flag after moving the ttm_bo_bulk_move_lru_tail() into
> amdgpu_vm_move_to_lru_tail() like below:
>
> void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
> struct amdgpu_vm *vm)
> {
> struct ttm_bo_global *glob = adev->mman.bdev.glob;
> struct amdgpu_vm_bo_base *bo_base;
>
> if (vm->bulk_moveable) {
> spin_lock(&glob->lru_lock);
> ttm_bo_bulk_move_lru_tail(&vm->lru_bulk_move);
> spin_unlock(&glob->lru_lock);
> return;
> }
>
> 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;
>
> 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);
> }
> spin_unlock(&glob->lru_lock);
>
> vm->bulk_moveable = true;
> }
>
> Thanks,
> Ray
>
>>> list_for_each_entry_safe(bo_base, tmp, &vm->evicted, vm_status) {
>>> struct amdgpu_bo *bo = bo_base->bo;
>>>
>>> @@ -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);
>>> }
>>>
>>> + vm->validated = true;
>>> if (bo->tbo.type != ttm_bo_type_kernel) {
>>> spin_lock(&vm->moved_lock);
>>> list_move(&bo_base->vm_status, &vm->moved);
>>> @@ -312,20 +355,14 @@ 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 (!bo->parent)
>>> - continue;
>>> + if (vm->validated)
>>> + return 0;
>>>
>>> - ttm_bo_move_to_lru_tail(&bo->tbo, NULL);
>>> - if (bo->shadow)
>>> - ttm_bo_move_to_lru_tail(&bo->shadow->tbo, NULL);
>>> - }
>>> + spin_lock(&glob->lru_lock);
>>> + ttm_bo_bulk_move_lru_tail(&vm->lru_bulk_move);
>>> spin_unlock(&glob->lru_lock);
>> Probably best to move that into amdgpu_vm_move_to_lru_tail() as well.
>>
>> Regards,
>> Christian.
>>
>>>
>>> - return r;
>>> + return 0;
>>> }
>>>
>>> /**
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>>> index 67a15d4..85d57bb 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 +227,11 @@ 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;
>>> + /* mark whether has bo validated on evicted list */
>>> + bool validated;
>>> };
>>>
>>> struct amdgpu_vm_manager {
>>> @@ -330,8 +336,11 @@ bool amdgpu_vm_need_pipeline_sync(struct amdgpu_ring *ring,
>>> void amdgpu_vm_check_compute_bug(struct amdgpu_device *adev);
>>>
>>> void amdgpu_vm_get_task_info(struct amdgpu_device *adev, unsigned int pasid,
>>> - struct amdgpu_task_info *task_info);
>>> + struct amdgpu_task_info *task_info);
>>>
>>> void amdgpu_vm_set_task_info(struct amdgpu_vm *vm);
>>>
>>> +void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
>>> + struct amdgpu_vm *vm);
>>> +
>>> #endif
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