[PATCH v3] drm/i915/guc: Use context hints for GT frequency

[Ivan Briano]

On Mon, Mar 4, 2024, at 3:34 PM, Vinay Belgaumkar wrote:
> Allow user to provide a low latency context hint. When set, KMD
> sends a hint to GuC which results in special handling for this
> context. SLPC will ramp the GT frequency aggressively every time
> it switches to this context. The down freq threshold will also be
> lower so GuC will ramp down the GT freq for this context more slowly.
> We also disable waitboost for this context as that will interfere with
> the strategy.
>
> We need to enable the use of SLPC Compute strategy during init, but
> it will apply only to contexts that set this bit during context
> creation.
>
> Userland can check whether this feature is supported using a new param-
> I915_PARAM_HAS_CONTEXT_FREQ_HINTS. This flag is true for all guc submission
> enabled platforms as they use SLPC for frequency management.
>
> The Mesa usage model for this flag is here -
> https://gitlab.freedesktop.org/sushmave/mesa/-/commits/compute_hint
>
> v2: Rename flags as per review suggestions (Rodrigo, Tvrtko).
> Also, use flag bits in intel_context as it allows finer control for
> toggling per engine if needed (Tvrtko).
>
> v3: Minor review comments (Tvrtko)
>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Sushma Venkatesh Reddy <sushma.venkatesh.reddy at intel.com>
> Acked-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> ---

Acked-by: Ivan Briano <ivan.briano at intel.com>