[Mesa-dev] [RFC PATCH] radeonsi: set a per-buffer flag that disables inter-process sharing (v2)

[Michel Dänzer]

On 18/07/17 04:08 PM, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> For lower overhead in the CS ioctl.
> Winsys allocators are not used with interprocess-sharable resources.
> 
> v2: It shouldn't crash anymore, but the kernel will reject the new flag.
> ---
>   src/gallium/drivers/radeon/r600_buffer_common.c |  7 +++++
>   src/gallium/drivers/radeon/radeon_winsys.h      | 20 +++++++++++---
>   src/gallium/winsys/amdgpu/drm/amdgpu_bo.c       | 36 ++++++++++++++++---------
>   src/gallium/winsys/radeon/drm/radeon_drm_bo.c   | 27 +++++++++++--------
>   4 files changed, 62 insertions(+), 28 deletions(-)
> 
> diff --git a/src/gallium/drivers/radeon/r600_buffer_common.c b/src/gallium/drivers/radeon/r600_buffer_common.c
> index dd1c209..2747ac4 100644
> --- a/src/gallium/drivers/radeon/r600_buffer_common.c
> +++ b/src/gallium/drivers/radeon/r600_buffer_common.c
> @@ -160,20 +160,27 @@ void r600_init_resource_fields(struct r600_common_screen *rscreen,
>   	}
>   
>   	/* Tiled textures are unmappable. Always put them in VRAM. */
>   	if ((res->b.b.target != PIPE_BUFFER && !rtex->surface.is_linear) ||
>   	    res->flags & R600_RESOURCE_FLAG_UNMAPPABLE) {
>   		res->domains = RADEON_DOMAIN_VRAM;
>   		res->flags |= RADEON_FLAG_NO_CPU_ACCESS |
>   			 RADEON_FLAG_GTT_WC;
>   	}
>   
> +	/* Only displayable single-sample textures can be shared between
> +	 * processes. */
> +	if (res->b.b.target == PIPE_BUFFER ||
> +	    res->b.b.nr_samples >= 2 ||
> +	    rtex->surface.micro_tile_mode != RADEON_MICRO_MODE_DISPLAY)
> +		res->flags |= RADEON_FLAG_NO_INTERPROCESS_SHARING;

We might want to share non-displayable textures at some point for 
performance, right? Will we still be able to flag some textures as 
non-shareable in that case?


> diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> index 97bbe23..06b8198 100644
> --- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> +++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> @@ -31,20 +31,24 @@
>   
>   #include "amdgpu_cs.h"
>   
>   #include "os/os_time.h"
>   #include "state_tracker/drm_driver.h"
>   #include <amdgpu_drm.h>
>   #include <xf86drm.h>
>   #include <stdio.h>
>   #include <inttypes.h>
>   
> +#ifndef AMDGPU_GEM_CREATE_NO_INTERPROCESS_SHARING
> +#define AMDGPU_GEM_CREATE_NO_INTERPROCESS_SHARING (1 << 6)
> +#endif

I advise against the #ifndef check for this kind of thing, because it 
prevents the preprocessor from warning about conflicting definitions.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer