[PATCH v3 1/5] drm/amdgpu: add UAPI for workload hints to ctx ioctl

[Christian König]

Well completely agree that we shouldn't have unused API. That's why I 
said we should remove the getting the hint from the UAPI.

But what's wrong with setting it after creating the context? Don't you 
know enough about the use case? I need to understand the background a 
bit better here.

Christian.

Am 22.03.23 um 15:05 schrieb Marek Olšák:
> The option to change the hint after context creation and get the hint 
> would be unused uapi, and AFAIK we are not supposed to add unused 
> uapi. What I asked is to change it to a uapi that userspace will 
> actually use.
>
> Marek
>
> On Tue, Mar 21, 2023 at 9:54 AM Christian König 
> <ckoenig.leichtzumerken at gmail.com> wrote:
>
>     Yes, I would like to avoid having multiple code paths for context
>     creation.
>
>     Setting it later on should be equally to specifying it on creation
>     since we only need it during CS.
>
>     Regards,
>     Christian.
>
>     Am 21.03.23 um 14:00 schrieb Sharma, Shashank:
>>
>>     [AMD Official Use Only - General]
>>
>>     When we started this patch series, the workload hint was a part
>>     of the ctx_flag only,
>>
>>     But we changed that after the design review, to make it more like
>>     how we are handling PSTATE.
>>
>>     Details:
>>
>>     https://patchwork.freedesktop.org/patch/496111/
>>
>>     Regards
>>
>>     Shashank
>>
>>     *From:*Marek Olšák <maraeo at gmail.com> <mailto:maraeo at gmail.com>
>>     *Sent:* 21 March 2023 04:05
>>     *To:* Sharma, Shashank <Shashank.Sharma at amd.com>
>>     <mailto:Shashank.Sharma at amd.com>
>>     *Cc:* amd-gfx at lists.freedesktop.org; Deucher, Alexander
>>     <Alexander.Deucher at amd.com> <mailto:Alexander.Deucher at amd.com>;
>>     Somalapuram, Amaranath <Amaranath.Somalapuram at amd.com>
>>     <mailto:Amaranath.Somalapuram at amd.com>; Koenig, Christian
>>     <Christian.Koenig at amd.com> <mailto:Christian.Koenig at amd.com>
>>     *Subject:* Re: [PATCH v3 1/5] drm/amdgpu: add UAPI for workload
>>     hints to ctx ioctl
>>
>>     I think we should do it differently because this interface will
>>     be mostly unused by open source userspace in its current form.
>>
>>     Let's set the workload hint in drm_amdgpu_ctx_in::flags, and that
>>     will be immutable for the lifetime of the context. No other
>>     interface is needed.
>>
>>     Marek
>>
>>     On Mon, Sep 26, 2022 at 5:41 PM Shashank Sharma
>>     <shashank.sharma at amd.com> wrote:
>>
>>         Allow the user to specify a workload hint to the kernel.
>>         We can use these to tweak the dpm heuristics to better match
>>         the workload for improved performance.
>>
>>         V3: Create only set() workload UAPI (Christian)
>>
>>         Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>>         Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
>>         ---
>>          include/uapi/drm/amdgpu_drm.h | 17 +++++++++++++++++
>>          1 file changed, 17 insertions(+)
>>
>>         diff --git a/include/uapi/drm/amdgpu_drm.h
>>         b/include/uapi/drm/amdgpu_drm.h
>>         index c2c9c674a223..23d354242699 100644
>>         --- a/include/uapi/drm/amdgpu_drm.h
>>         +++ b/include/uapi/drm/amdgpu_drm.h
>>         @@ -212,6 +212,7 @@ union drm_amdgpu_bo_list {
>>          #define AMDGPU_CTX_OP_QUERY_STATE2     4
>>          #define AMDGPU_CTX_OP_GET_STABLE_PSTATE        5
>>          #define AMDGPU_CTX_OP_SET_STABLE_PSTATE        6
>>         +#define AMDGPU_CTX_OP_SET_WORKLOAD_PROFILE     7
>>
>>          /* GPU reset status */
>>          #define AMDGPU_CTX_NO_RESET            0
>>         @@ -252,6 +253,17 @@ union drm_amdgpu_bo_list {
>>          #define AMDGPU_CTX_STABLE_PSTATE_MIN_MCLK  3
>>          #define AMDGPU_CTX_STABLE_PSTATE_PEAK  4
>>
>>         +/* GPU workload hints, flag bits 8-15 */
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_SHIFT     8
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_MASK      (0xff <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_NONE      (0 <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_3D        (1 <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_VIDEO     (2 <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_VR        (3 <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_COMPUTE   (4 <<
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +#define AMDGPU_CTX_WORKLOAD_HINT_MAX
>>         AMDGPU_CTX_WORKLOAD_HINT_COMPUTE
>>         +#define AMDGPU_CTX_WORKLOAD_INDEX(n)      (n >>
>>         AMDGPU_CTX_WORKLOAD_HINT_SHIFT)
>>         +
>>          struct drm_amdgpu_ctx_in {
>>                 /** AMDGPU_CTX_OP_* */
>>                 __u32   op;
>>         @@ -281,6 +293,11 @@ union drm_amdgpu_ctx_out {
>>                                 __u32   flags;
>>                                 __u32   _pad;
>>                         } pstate;
>>         +
>>         +               struct {
>>         +                       __u32   flags;
>>         +                       __u32   _pad;
>>         +               } workload;
>>          };
>>
>>          union drm_amdgpu_ctx {
>>         -- 
>>         2.34.1
>>
>
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