[Intel-gfx] [PATCH 5/6] drm/i915: Expose RPCS (SSEU) configuration to userspace (Gen11 only)
Takashi Iwai
tiwai at suse.de
Mon Jan 21 21:33:14 UTC 2019
On Tue, 15 Jan 2019 15:47:32 +0100,
Joonas Lahtinen wrote:
>
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> We want to allow userspace to reconfigure the subslice configuration on a
> per context basis.
>
> This is required for the functional requirement of shutting down non-VME
> enabled sub-slices on Gen11 parts.
>
> To do so, we expose a context parameter to allow adjustment of the RPCS
> register stored within the context image (and currently not accessible via
> LRI).
>
> If the context is adjusted before first use or whilst idle, the adjustment
> is for "free"; otherwise if the context is active we queue a request to do
> so (using the kernel context), following all other activity by that
> context, which is also marked as barrier for all following submission
> against the same context.
>
> Since the overhead of device re-configuration during context switching can
> be significant, especially in multi-context workloads, we limit this new
> uAPI to only support the Gen11 VME use case. In this use case either the
> device is fully enabled, and exactly one slice and half of the subslices
> are enabled.
>
> Example usage:
>
> struct drm_i915_gem_context_param_sseu sseu = { };
> struct drm_i915_gem_context_param arg =
> { .param = I915_CONTEXT_PARAM_SSEU,
> .ctx_id = gem_context_create(fd),
> .size = sizeof(sseu),
> .value = to_user_pointer(&sseu)
> };
>
> /* Query device defaults. */
> gem_context_get_param(fd, &arg);
>
> /* Set VME configuration on a 1x6x8 part. */
> sseu.slice_mask = 0x1;
> sseu.subslice_mask = 0xe0;
> gem_context_set_param(fd, &arg);
>
> v2: Fix offset of CTX_R_PWR_CLK_STATE in intel_lr_context_set_sseu() (Lionel)
>
> v3: Add ability to program this per engine (Chris)
>
> v4: Move most get_sseu() into i915_gem_context.c (Lionel)
>
> v5: Validate sseu configuration against the device's capabilities (Lionel)
>
> v6: Change context powergating settings through MI_SDM on kernel context (Chris)
>
> v7: Synchronize the requests following a powergating setting change using a global
> dependency (Chris)
> Iterate timelines through dev_priv.gt.active_rings (Tvrtko)
> Disable RPCS configuration setting for non capable users (Lionel/Tvrtko)
>
> v8: s/union intel_sseu/struct intel_sseu/ (Lionel)
> s/dev_priv/i915/ (Tvrtko)
> Change uapi class/instance fields to u16 (Tvrtko)
> Bump mask fields to 64bits (Lionel)
> Don't return EPERM when dynamic sseu is disabled (Tvrtko)
>
> v9: Import context image into kernel context's ppgtt only when
> reconfiguring powergated slice/subslices (Chris)
> Use aliasing ppgtt when needed (Michel)
>
> Tvrtko Ursulin:
>
> v10:
> * Update for upstream changes.
> * Request submit needs a RPM reference.
> * Reject on !FULL_PPGTT for simplicity.
> * Pull out get/set param to helpers for readability and less indent.
> * Use i915_request_await_dma_fence in add_global_barrier to skip waits
> on the same timeline and avoid GEM_BUG_ON.
> * No need to explicitly assign a NULL pointer to engine in legacy mode.
> * No need to move gen8_make_rpcs up.
> * Factored out global barrier as prep patch.
> * Allow to only CAP_SYS_ADMIN if !Gen11.
>
> v11:
> * Remove engine vfunc in favour of local helper. (Chris Wilson)
> * Stop retiring requests before updates since it is not needed
> (Chris Wilson)
> * Implement direct CPU update path for idle contexts. (Chris Wilson)
> * Left side dependency needs only be on the same context timeline.
> (Chris Wilson)
> * It is sufficient to order the timeline. (Chris Wilson)
> * Reject !RCS configuration attempts with -ENODEV for now.
>
> v12:
> * Rebase for make_rpcs.
>
> v13:
> * Centralize SSEU normalization to make_rpcs.
> * Type width checking (uAPI <-> implementation).
> * Gen11 restrictions uAPI checks.
> * Gen11 subslice count differences handling.
> Chris Wilson:
> * args->size handling fixes.
> * Update context image from GGTT.
> * Postpone context image update to pinning.
> * Use i915_gem_active_raw instead of last_request_on_engine.
>
> v14:
> * Add activity tracker on intel_context to fix the lifetime issues
> and simplify the code. (Chris Wilson)
>
> v15:
> * Fix context pin leak if no space in ring by simplifying the
> context pinning sequence.
>
> v16:
> * Rebase for context get/set param locking changes.
> * Just -ENODEV on !Gen11. (Joonas)
>
> v17:
> * Fix one Gen11 subslice enablement rule.
> * Handle error from i915_sw_fence_await_sw_fence_gfp. (Chris Wilson)
>
> v18:
> * Update commit message. (Joonas)
> * Restrict uAPI to VME use case. (Joonas)
>
> v19:
> * Rebase.
>
> v20:
> * Rebase for ce->active_tracker.
>
> v21:
> * Rebase for IS_GEN changes.
>
> v22:
> * Reserve uAPI for flags straight away. (Chris Wilson)
>
> v23:
> * Rebase for RUNTIME_INFO.
>
> v24:
> * Added some headline docs for the uapi usage. (Joonas/Chris)
>
> v25:
> * Renamed class/instance to engine_class/engine_instance to avoid clash
> with C++ keyword. (Tony Ye)
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100899
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107634
> Issue: https://github.com/intel/media-driver/issues/267
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Zhipeng Gong <zhipeng.gong at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Tony Ye <tony.ye at intel.com>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> # v21
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
The change looks good to me.
Feel free to take my ack
Acked-by: Takashi Iwai <tiwai at suse.de>
thanks,
Takashi
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