[PATCH v5 0/5] drm/ttm,amdgpu: Introduce LRU bulk move functionality

[Huang Rui]

On Wed, Aug 22, 2018 at 04:24:02PM +0800, Christian König wrote:
> Please commit patches #1, #2 and #3, doesn't make much sense to send 
> them out even more often.
> 
> Jerry's comments on patch #4 sound valid to me as well, but with those 
> minor issues fixes/commented I think we can commit it.
> 
> Thanks for taking care of this,
> Christian.

OK. Thanks to your time.

Thanks,
Ray

> 
> Am 22.08.2018 um 09:52 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:
> > Commit 0bbf32026cf5ba41e9922b30e26e1bed1ecd38ae ("drm/amdgpu: band aid
> > validating VM PTs")
> >
> > 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.
> >
> > Changes from V3 -> V4:
> > - Move the amdgpu_vm_move_to_lru_tail after command submission, at that time,
> >    all bo will be back on idle list.
> >
> > Changes from V4 -> V5:
> > - Remove amdgpu_vm_move_to_lru_tail_by_list(), use bulk_moveable instread of
> >    validated, and move ttm_bo_bulk_move_lru_tail() also into
> >    amdgpu_vm_move_to_lru_tail().
> >
> > Thanks,
> > Ray
> >
> > 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 (v5)
> >    drm/amdgpu: move PD/PT bos on LRU again
> >
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 10 +++++
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 68 +++++++++++++++++++----------
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 11 ++++-
> >   drivers/gpu/drm/ttm/ttm_bo.c           | 78 +++++++++++++++++++++++++++++++++-
> >   include/drm/ttm/ttm_bo_api.h           | 16 ++++++-
> >   include/drm/ttm/ttm_bo_driver.h        | 28 ++++++++++++
> >   6 files changed, 186 insertions(+), 25 deletions(-)
> >
>