On 1/29/2025 8:50 PM, Eric Huang wrote:
> In some ASICs L2 cache info may miss in kfd topology,
> because the first bitmap may be empty, that means
> the first cu may be inactive, so to find the first
> active cu will solve the issue.
>
> Signed-off-by: Eric Huang <jinhuieric.huang@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> index 4936697e6fc2..73d95041a388 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> @@ -1665,17 +1665,31 @@ static int fill_in_l2_l3_pcache(struct kfd_cache_properties **props_ext,
> int cache_type, unsigned int cu_processor_id,
> struct kfd_node *knode)
> {
> - unsigned int cu_sibling_map_mask;
> + unsigned int cu_sibling_map_mask = 0;
> int first_active_cu;
> int i, j, k, xcc, start, end;
> int num_xcc = NUM_XCC(knode->xcc_mask);
> struct kfd_cache_properties *pcache = NULL;
> enum amdgpu_memory_partition mode;
> struct amdgpu_device *adev = knode->adev;
> + bool found = false;
>
> start = ffs(knode->xcc_mask) - 1;
> end = start + num_xcc;
> - cu_sibling_map_mask = cu_info->bitmap[start][0][0];
> +
> + /* To find the bitmap in the first active cu */
> + for (xcc = start; xcc < end && !found; xcc++) {
It seems there is an assumption made here that a CU in one XCC could
share this cache with CU in another XCC. This is not true for GFX 9.4.3
SOCs. In those, a CU in XCC0 doesn't share L2 with CU in XCC1.
Thanks,
Lijo
> + for (i = 0; i < gfx_info->max_shader_engines && !found; i++) {
> + for (j = 0; j < gfx_info->max_sh_per_se && !found; j++) {
> + if (cu_info->bitmap[xcc][i % 4][j % 4]) {
> + cu_sibling_map_mask =
> + cu_info->bitmap[xcc][i % 4][j % 4];
> + found = true;
> + }
> + }
> + }
> + }
> +
> cu_sibling_map_mask &=
> ((1 << pcache_info[cache_type].num_cu_shared) - 1);
> first_active_cu = ffs(cu_sibling_map_mask);
