github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-27 16:44:58 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

drm/v3d: Reduce the alignment of the node allocation

Browse Source 
Currently, we are using an alignment of 128 kB to insert a node, which
ends up wasting memory as we perform plenty of small BOs allocations
(<= 4 kB). We require that allocations are aligned to 128Kb so for any
allocation smaller than that, we are wasting the difference.

This implies that we cannot effectively use the whole 4 GB address space
available for the GPU in the RPi 4. Currently, we can allocate up to
32000 BOs of 4 kB (~140 MB) and 3000 BOs of 400 kB (~1,3 GB). This can be
quite limiting for applications that have a high memory requirement, such
as vkoverhead [1].

By reducing the page alignment to 4 kB, we can allocate up to 1000000 BOs
of 4 kB (~4 GB) and 10000 BOs of 400 kB (~4 GB). Moreover, by performing
benchmarks, we were able to attest that reducing the page alignment to
4 kB can provide a general performance improvement in OpenGL
applications (e.g. glmark2).

Therefore, this patch reduces the alignment of the node allocation to 4
kB, which will allow RPi users to explore the whole 4GB virtual
address space provided by the hardware. Also, this patch allow users to
fully run vkoverhead in the RPi 4/5, solving the issue reported in [1].

[1] https://github.com/zmike/vkoverhead/issues/14

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923141348.2422499-8-mcanal@igalia.com
This commit is contained in:
Maíra Canal 2024-09-23 10:55:11 -03:00
parent be431dfec9
commit 8dd6074d47
No known key found for this signature in database
GPG Key ID: 6E388F05AB35B7CF
2 changed files with 1 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpu/drm/v3d/v3d_bo.c
View File

@ -123,7 +123,7 @@ v3d_bo_create_finish(struct drm_gem_object *obj)
*/
ret = drm_mm_insert_node_generic(&v3d->mm, &bo->node,
obj->size >> V3D_MMU_PAGE_SHIFT,
GMP_GRANULARITY >> V3D_MMU_PAGE_SHIFT, 0, 0);
SZ_4K >> V3D_MMU_PAGE_SHIFT, 0, 0);
spin_unlock(&v3d->mm_lock);
if (ret)
return ret;

2
drivers/gpu/drm/v3d/v3d_drv.h
View File

@ -19,8 +19,6 @@ struct clk;
struct platform_device;
struct reset_control;
#define GMP_GRANULARITY (128 * 1024)
#define V3D_MMU_PAGE_SHIFT 12
#define V3D_MAX_QUEUES (V3D_CPU + 1)