Re: [PATCH v3 0/2] Fix serialization on burst of unbinds - v2

[Matthew Brost <matthew.brost@intel.com>]

On Fri, Oct 24, 2025 at 03:20:45PM -0700, Matthew Brost wrote:
> Attempting to resolve part of [1]; this solution differs than v1 [2] by
> changing last fence semantics detailed in the patches.
> 
> Overview of issue in [1]:
> 
> When a burst of unbind jobs is issued, a dependency chain can form
> between the TLB invalidation of a previous unbind job and the current
> one. This leads to undesirable serialization, causing current jobs to
> wait unnecessarily for prior TLB invalidations, execute on the GPU when
> not needed, and significantly slow down the unbind burst—resulting in up
> to a 4× slowdown.
>  
> Matt
> 
> [1] https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6047
> [2] https://patchwork.freedesktop.org/series/156144/
> 

Don't review this one, still issues here.

Matt

> Matthew Brost (2):
>   drm/xe: Add last fence attachment to TLB invalidation job queues
>   drm/xe: Decouple bind queue last fence from TLB invalidations
> 
>  drivers/gpu/drm/xe/xe_exec_queue.c       | 105 ++++++++++++++++++++++-
>  drivers/gpu/drm/xe/xe_exec_queue.h       |  18 ++++
>  drivers/gpu/drm/xe/xe_exec_queue_types.h |   5 ++
>  drivers/gpu/drm/xe/xe_pt.c               |  64 +++++---------
>  drivers/gpu/drm/xe/xe_sync.c             |  58 +++++++++++--
>  drivers/gpu/drm/xe/xe_vm.c               |  60 +++++++------
>  6 files changed, 234 insertions(+), 76 deletions(-)
> 
> -- 
> 2.34.1
>