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[0/6] drm/v3d: Improve Performance Counters handling

Message ID 20240508143306.2435304-2-mcanal@igalia.com (mailing list archive)
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Series drm/v3d: Improve Performance Counters handling | expand

Message

Maíra Canal May 8, 2024, 2:30 p.m. UTC 
This series has the intention to address two issues with Performance Counters
on V3D:

1. Update the number of Performance Counters for V3D 7.1 
	
V3D 7.1 has 93 performance counters, while V3D 4.2 has only 87. Although the
series [1] enabled support for V3D 7.1, it didn’t replace the maximum number of
performance counters. This led to errors in user space as the Vulkan driver
updated the maximum number of performance counters, but the kernel didn’t. 
    
Currently, the user space can request values for performance counters that
are greater than 87 and the kernel will return an error instead of the values.
That’s why `dEQP-VK.query_pool.performance_query.*` currently fails on Mesa
CI [2]. This series intends to fix the `dEQP-VK.query_pool.performance_query.*`
fail.
    
2. Make the kernel able to provide the Performance Counter descriptions
    
Although all the management of the Performance Monitors is done through IOCTLs,
which means that the code is in the kernel, the performance counter descriptions
are in Mesa. This means two things: (#1) only Mesa has access to the descriptions
and (#2) we can have inconsistencies between the information provided by Mesa
and the kernel, as seen in the first issue addressed by this series.
	
To minimize the risk of inconsistencies, this series proposes to use the kernel
as a “single source of truth”. Therefore, if there are any changes to the
performance monitors, all the changes must be done only in the kernel. This
means that all information about the maximum number of performance counters and
all the descriptions will now be retrieved from the kernel. 

This series is coupled with a Mesa series [3] that enabled the use of the new
IOCTL. I appreciate any feedback from both the kernel and Mesa implementations.

[1] https://lore.kernel.org/dri-devel/20231031073859.25298-1-itoral@igalia.com/
[2] https://gitlab.freedesktop.org/mesa/mesa/-/commit/ea1f09a5f21839f4f3b93610b58507c4bd9b9b81
[3] https://gitlab.freedesktop.org/mairacanal/mesa/-/tree/v3dv/fix-perfcnt

Best Regards,
- Maíra Canal

Maíra Canal (6):
  drm/v3d: Add Performance Counters descriptions for V3D 4.2 and 7.1
  drm/v3d: Different V3D versions can have different number of perfcnt
  drm/v3d: Create a new V3D parameter for the maximum number of perfcnt
  drm/v3d: Create new IOCTL to expose performance counters information
  drm/v3d: Use V3D_MAX_COUNTERS instead of V3D_PERFCNT_NUM
  drm/v3d: Deprecate the use of the Performance Counters enum

 drivers/gpu/drm/v3d/v3d_drv.c                 |  11 +
 drivers/gpu/drm/v3d/v3d_drv.h                 |  14 +-
 drivers/gpu/drm/v3d/v3d_perfmon.c             |  36 ++-
 .../gpu/drm/v3d/v3d_performance_counters.h    | 208 ++++++++++++++++++
 drivers/gpu/drm/v3d/v3d_sched.c               |   2 +-
 include/uapi/drm/v3d_drm.h                    |  44 ++++
 6 files changed, 312 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/v3d/v3d_performance_counters.h

Comments

Iago Toral May 9, 2024, 6:15 a.m. UTC | #1 
Hi Maíra,

I made a couple of minor comments, with those addressed the series is:

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>

Thanks a lot for this!,
Iago

El mié, 08-05-2024 a las 11:30 -0300, Maíra Canal escribió:
> This series has the intention to address two issues with Performance
> Counters
> on V3D:
> 
> 1. Update the number of Performance Counters for V3D 7.1 
> 	
> V3D 7.1 has 93 performance counters, while V3D 4.2 has only 87.
> Although the
> series [1] enabled support for V3D 7.1, it didn’t replace the maximum
> number of
> performance counters. This led to errors in user space as the Vulkan
> driver
> updated the maximum number of performance counters, but the kernel
> didn’t. 
>     
> Currently, the user space can request values for performance counters
> that
> are greater than 87 and the kernel will return an error instead of
> the values.
> That’s why `dEQP-VK.query_pool.performance_query.*` currently fails
> on Mesa
> CI [2]. This series intends to fix the `dEQP-
> VK.query_pool.performance_query.*`
> fail.
>     
> 2. Make the kernel able to provide the Performance Counter
> descriptions
>     
> Although all the management of the Performance Monitors is done
> through IOCTLs,
> which means that the code is in the kernel, the performance counter
> descriptions
> are in Mesa. This means two things: (#1) only Mesa has access to the
> descriptions
> and (#2) we can have inconsistencies between the information provided
> by Mesa
> and the kernel, as seen in the first issue addressed by this series.
> 	
> To minimize the risk of inconsistencies, this series proposes to use
> the kernel
> as a “single source of truth”. Therefore, if there are any changes to
> the
> performance monitors, all the changes must be done only in the
> kernel. This
> means that all information about the maximum number of performance
> counters and
> all the descriptions will now be retrieved from the kernel. 
> 
> This series is coupled with a Mesa series [3] that enabled the use of
> the new
> IOCTL. I appreciate any feedback from both the kernel and Mesa
> implementations.
> 
> [1]
> https://lore.kernel.org/dri-devel/20231031073859.25298-1-itoral@igalia.com/
> [2]
> https://gitlab.freedesktop.org/mesa/mesa/-/commit/ea1f09a5f21839f4f3b93610b58507c4bd9b9b81
> [3]
> https://gitlab.freedesktop.org/mairacanal/mesa/-/tree/v3dv/fix-perfcnt
> 
> Best Regards,
> - Maíra Canal
> 
> Maíra Canal (6):
>   drm/v3d: Add Performance Counters descriptions for V3D 4.2 and 7.1
>   drm/v3d: Different V3D versions can have different number of
> perfcnt
>   drm/v3d: Create a new V3D parameter for the maximum number of
> perfcnt
>   drm/v3d: Create new IOCTL to expose performance counters
> information
>   drm/v3d: Use V3D_MAX_COUNTERS instead of V3D_PERFCNT_NUM
>   drm/v3d: Deprecate the use of the Performance Counters enum
> 
>  drivers/gpu/drm/v3d/v3d_drv.c                 |  11 +
>  drivers/gpu/drm/v3d/v3d_drv.h                 |  14 +-
>  drivers/gpu/drm/v3d/v3d_perfmon.c             |  36 ++-
>  .../gpu/drm/v3d/v3d_performance_counters.h    | 208
> ++++++++++++++++++
>  drivers/gpu/drm/v3d/v3d_sched.c               |   2 +-
>  include/uapi/drm/v3d_drm.h                    |  44 ++++
>  6 files changed, 312 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/v3d/v3d_performance_counters.h
>