[PATCH v3 0/5] drm/ttm,amdgpu: Introduce LRU bulk move functionality

Huang Rui ray.huang at amd.com
Fri Aug 17 10:06:29 UTC 2018


On Thu, Aug 16, 2018 at 08:41:44AM +0800, Dieter Nützel wrote:
> For the series
> 
> Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de>
> 
> on RX580,
> amd-staging-drm-next
> #5024f8dfe478
> 

Thank you so much, will add tested-by in next version.

Thanks,
Ray

> Dieter
> 
> Am 13.08.2018 11:58, schrieb Huang Rui:
> > The idea and proposal is originally from Christian, and I continue to 
> > work to
> > deliver it.
> > 
> > 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.
> > 
> > Changes from V1 -> V2:
> > - Fix to missed the BOs in relocated/moved that should be also moved to 
> > the end
> >   of LRU.
> > 
> > Changes from V2 -> V3:
> > - Remove unused parameter and use list_for_each_entry instead of the 
> > one with
> >   save entry.
> > 
> > Thanks,
> > Rui
> > 
> > Christian König (2):
> >   drm/ttm: add helper structures for bulk moves on lru list
> >   drm/ttm: revise ttm_bo_move_to_lru_tail to support bulk moves
> > 
> > Huang Rui (3):
> >   drm/ttm: add bulk move function on LRU
> >   drm/amdgpu: use bulk moves for efficient VM LRU handling (v3)
> >   drm/amdgpu: move PD/PT bos on LRU again
> > 
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 75 
> > ++++++++++++++++++++++++--------
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h |  4 ++
> >  drivers/gpu/drm/ttm/ttm_bo.c           | 78 
> > +++++++++++++++++++++++++++++++++-
> >  include/drm/ttm/ttm_bo_api.h           | 16 ++++++-
> >  include/drm/ttm/ttm_bo_driver.h        | 28 ++++++++++++
> >  5 files changed, 182 insertions(+), 19 deletions(-)


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