On Mon, Jan 11, 2021 at 08:51:23PM +0000, Chris Wilson wrote: > Quoting Rodrigo Vivi (2021-01-11 17:35:12) > > On Sun, Jan 10, 2021 at 03:03:54PM +0000, Chris Wilson wrote: > > > MEDIA_STATE_VFE only accepts the 'maximum number of threads' in the > > > range [0, n-1] where n is #EU * (#threads/EU) with the number of threads > > > based on plaform and the number of EU based on the number of slices and > > > subslices. This is a fixed number per platform/gt, so appropriately > > > limit the number of threads we spawn to match the device. > > > > > > v2: Oversaturate the system with tasks to force execution on every HW > > > thread; if the thread idles it is returned to the pool and may be reused > > > again before an unused thread. > > > > > > v3: Fix more state commands, which was causing Baytrail to barf. > > > > CI is still not happy with byt right? or is that false positive? > > After v3, ivb still failed. > > > > v4: STATE_CACHE_INVALIDATE requires a stall on Ivybridge > > Right now with the multiple pipecontrls around the PIPELINE_SELECT *and* > STATE_BASE, CI has been happy for multiple runs. I was able to reproduce > the same selftests failures and confirm that we do not see any of those > failures in a thousand iterations. High level of confidence, but since > we are dealing with empirical results with cross-referencing to mesa who > also have seen similar undocumented failures, there's still an element > of doubt as to whether it is truly watertight. > > The CI results for this series passed on the all important ivb,byt,hsw. great! > > > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2024 > > > Fixes: 47f8253d2b89 ("drm/i915/gen7: Clear all EU/L3 residual contexts") > > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > > > Cc: Prathap Kumar Valsan <prathap.kumar.valsan@xxxxxxxxx> > > > Cc: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx> > > > Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx> > > > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > > > Cc: Randy Wright <rwright@xxxxxxx> > > > Cc: stable@xxxxxxxxxxxxxxx # v5.7+ > > > --- > > > drivers/gpu/drm/i915/gt/gen7_renderclear.c | 157 ++++++++++++--------- > > > 1 file changed, 94 insertions(+), 63 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/gt/gen7_renderclear.c b/drivers/gpu/drm/i915/gt/gen7_renderclear.c > > > index d93d85cd3027..f32a8e8040b2 100644 > > > --- a/drivers/gpu/drm/i915/gt/gen7_renderclear.c > > > +++ b/drivers/gpu/drm/i915/gt/gen7_renderclear.c > > > @@ -7,8 +7,6 @@ > > > #include "i915_drv.h" > > > #include "intel_gpu_commands.h" > > > > > > -#define MAX_URB_ENTRIES 64 > > > -#define STATE_SIZE (4 * 1024) > > > #define GT3_INLINE_DATA_DELAYS 0x1E00 > > > #define batch_advance(Y, CS) GEM_BUG_ON((Y)->end != (CS)) > > > > > > @@ -34,38 +32,59 @@ struct batch_chunk { > > > }; > > > > > > struct batch_vals { > > > - u32 max_primitives; > > > - u32 max_urb_entries; > > > - u32 cmd_size; > > > - u32 state_size; > > > + u32 max_threads; > > > u32 state_start; > > > - u32 batch_size; > > > + u32 surface_start; > > > u32 surface_height; > > > u32 surface_width; > > > - u32 scratch_size; > > > - u32 max_size; > > > + u32 size; > > > }; > > > > > > +static inline int num_primitives(const struct batch_vals *bv) > > > +{ > > > + /* > > > + * We need to saturate the GPU with work in order to dispatch > > > + * a shader on every HW thread, and clear the thread-local registers. > > > + * In short, we have to dispatch work faster than the shaders can > > > + * run in order to fill occupy each HW thread. > > > + */ > > > + return bv->max_threads; > > > +} > > > + > > > static void > > > batch_get_defaults(struct drm_i915_private *i915, struct batch_vals *bv) > > > { > > > if (IS_HASWELL(i915)) { > > > - bv->max_primitives = 280; > > > - bv->max_urb_entries = MAX_URB_ENTRIES; > > > + switch (INTEL_INFO(i915)->gt) { > > > + default: > > > + case 1: > > > + bv->max_threads = 70; > > > + break; > > > + case 2: > > > + bv->max_threads = 140; > > > + break; > > > + case 3: > > > + bv->max_threads = 280; > > > + break; > > > + } > > > bv->surface_height = 16 * 16; > > > bv->surface_width = 32 * 2 * 16; > > > } else { > > > - bv->max_primitives = 128; > > > - bv->max_urb_entries = MAX_URB_ENTRIES / 2; > > > + switch (INTEL_INFO(i915)->gt) { > > > + default: > > > + case 1: /* including vlv */ > > > + bv->max_threads = 36; > > > + break; > > > + case 2: > > > + bv->max_threads = 128; > > > + break; > > > + } > > > bv->surface_height = 16 * 8; > > > bv->surface_width = 32 * 16; > > > > all the values above matches the spec. > > > > > } > > > - bv->cmd_size = bv->max_primitives * 4096; > > > - bv->state_size = STATE_SIZE; > > > - bv->state_start = bv->cmd_size; > > > - bv->batch_size = bv->cmd_size + bv->state_size; > > > - bv->scratch_size = bv->surface_height * bv->surface_width; > > > - bv->max_size = bv->batch_size + bv->scratch_size; > > > + bv->state_start = round_up(SZ_1K + num_primitives(bv) * 64, SZ_4K); > > > + bv->surface_start = bv->state_start + SZ_4K; > > > + bv->size = bv->surface_start + bv->surface_height * bv->surface_width; > > > > I liked this batch values simplification... > > > > > } > > > > > > static void batch_init(struct batch_chunk *bc, > > > @@ -155,7 +174,8 @@ static u32 > > > gen7_fill_binding_table(struct batch_chunk *state, > > > const struct batch_vals *bv) > > > { > > > - u32 surface_start = gen7_fill_surface_state(state, bv->batch_size, bv); > > > + u32 surface_start = > > > + gen7_fill_surface_state(state, bv->surface_start, bv); > > > u32 *cs = batch_alloc_items(state, 32, 8); > > > u32 offset = batch_offset(state, cs); > > > > > > @@ -214,9 +234,9 @@ static void > > > gen7_emit_state_base_address(struct batch_chunk *batch, > > > u32 surface_state_base) > > > { > > > - u32 *cs = batch_alloc_items(batch, 0, 12); > > > + u32 *cs = batch_alloc_items(batch, 0, 10); > > > > > > - *cs++ = STATE_BASE_ADDRESS | (12 - 2); > > > + *cs++ = STATE_BASE_ADDRESS | (10 - 2); > > > /* general */ > > > *cs++ = batch_addr(batch) | BASE_ADDRESS_MODIFY; > > > /* surface */ > > > @@ -233,8 +253,6 @@ gen7_emit_state_base_address(struct batch_chunk *batch, > > > *cs++ = BASE_ADDRESS_MODIFY; > > > *cs++ = 0; > > > *cs++ = BASE_ADDRESS_MODIFY; > > > - *cs++ = 0; > > > - *cs++ = 0; > > > > why don't we need this anymore? > > It was incorrect, gen7 is just (10-2). The last two were extraneous > padding. > > > > batch_advance(batch, cs); > > > } > > > > > > @@ -244,8 +262,7 @@ gen7_emit_vfe_state(struct batch_chunk *batch, > > > u32 urb_size, u32 curbe_size, > > > u32 mode) > > > { > > > - u32 urb_entries = bv->max_urb_entries; > > > - u32 threads = bv->max_primitives - 1; > > > + u32 threads = bv->max_threads - 1; > > > u32 *cs = batch_alloc_items(batch, 32, 8); > > > > > > *cs++ = MEDIA_VFE_STATE | (8 - 2); > > > @@ -254,7 +271,7 @@ gen7_emit_vfe_state(struct batch_chunk *batch, > > > *cs++ = 0; > > > > > > /* number of threads & urb entries for GPGPU vs Media Mode */ > > > - *cs++ = threads << 16 | urb_entries << 8 | mode << 2; > > > + *cs++ = threads << 16 | 1 << 8 | mode << 2; > > > > > > *cs++ = 0; > > > > > > @@ -293,17 +310,12 @@ gen7_emit_media_object(struct batch_chunk *batch, > > > { > > > unsigned int x_offset = (media_object_index % 16) * 64; > > > unsigned int y_offset = (media_object_index / 16) * 16; > > > - unsigned int inline_data_size; > > > - unsigned int media_batch_size; > > > - unsigned int i; > > > + unsigned int pkt = 6 + 3; > > > u32 *cs; > > > > > > - inline_data_size = 112 * 8; > > > - media_batch_size = inline_data_size + 6; > > > + cs = batch_alloc_items(batch, 8, pkt); > > > > > > - cs = batch_alloc_items(batch, 8, media_batch_size); > > > - > > > - *cs++ = MEDIA_OBJECT | (media_batch_size - 2); > > > + *cs++ = MEDIA_OBJECT | (pkt - 2); > > > > > > /* interface descriptor offset */ > > > *cs++ = 0; > > > @@ -317,25 +329,44 @@ gen7_emit_media_object(struct batch_chunk *batch, > > > *cs++ = 0; > > > > > > /* inline */ > > > - *cs++ = (y_offset << 16) | (x_offset); > > > + *cs++ = y_offset << 16 | x_offset; > > > *cs++ = 0; > > > *cs++ = GT3_INLINE_DATA_DELAYS; > > > - for (i = 3; i < inline_data_size; i++) > > > - *cs++ = 0; > > > > why? > > We don't use the extra urb data, and worse the extra inline data slows > down the CP to be slower than the thread dispatch. That was causing the > issue that the same HW thread was servicing multiple MEDIA_OBJECTS, and > we did not then clear all the thread-local registers across the EU (as > some threads never executed our shader). And that was the cause of the > validation failures in v1. > > [The first clue was that if we submitted more a few more objects than > threads with v1, it takes twice as long, and passes the validation test. > Now, touch wood, it appears that we are able to saturate the HW threads > with an equal number of objects, so every HW thread does exactly one > iteration of the shader.] > > > > batch_advance(batch, cs); > > > } > > > > > > static void gen7_emit_pipeline_flush(struct batch_chunk *batch) > > > { > > > - u32 *cs = batch_alloc_items(batch, 0, 5); > > > + u32 *cs = batch_alloc_items(batch, 0, 4); > > > > > > - *cs++ = GFX_OP_PIPE_CONTROL(5); > > > - *cs++ = PIPE_CONTROL_STATE_CACHE_INVALIDATE | > > > - PIPE_CONTROL_GLOBAL_GTT_IVB; > > > + *cs++ = GFX_OP_PIPE_CONTROL(4); > > > + *cs++ = PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH | > > > + PIPE_CONTROL_DEPTH_CACHE_FLUSH | > > > + PIPE_CONTROL_DC_FLUSH_ENABLE | > > > + PIPE_CONTROL_CS_STALL; > > > *cs++ = 0; > > > *cs++ = 0; > > > + > > > + batch_advance(batch, cs); > > > +} > > > + > > > +static void gen7_emit_pipeline_invalidate(struct batch_chunk *batch) > > > +{ > > > + u32 *cs = batch_alloc_items(batch, 0, 8); > > > + > > > + /* ivb: Stall before STATE_CACHE_INVALIDATE */ > > > + *cs++ = GFX_OP_PIPE_CONTROL(4); > > > + *cs++ = PIPE_CONTROL_STALL_AT_SCOREBOARD | > > > + PIPE_CONTROL_CS_STALL; > > > *cs++ = 0; > > > + *cs++ = 0; > > > + > > > + *cs++ = GFX_OP_PIPE_CONTROL(4); > > > + *cs++ = PIPE_CONTROL_STATE_CACHE_INVALIDATE; > > > + *cs++ = 0; > > > + *cs++ = 0; > > > + > > > batch_advance(batch, cs); > > > } > > > > > > @@ -344,34 +375,34 @@ static void emit_batch(struct i915_vma * const vma, > > > const struct batch_vals *bv) > > > { > > > struct drm_i915_private *i915 = vma->vm->i915; > > > - unsigned int desc_count = 64; > > > - const u32 urb_size = 112; > > > + const unsigned int desc_count = 1; > > > + const unsigned int urb_size = 1; > > > struct batch_chunk cmds, state; > > > - u32 interface_descriptor; > > > + u32 descriptors; > > > unsigned int i; > > > > > > - batch_init(&cmds, vma, start, 0, bv->cmd_size); > > > - batch_init(&state, vma, start, bv->state_start, bv->state_size); > > > + batch_init(&cmds, vma, start, 0, bv->state_start); > > > + batch_init(&state, vma, start, bv->state_start, SZ_4K); > > > > > > - interface_descriptor = > > > - gen7_fill_interface_descriptor(&state, bv, > > > - IS_HASWELL(i915) ? > > > - &cb_kernel_hsw : > > > - &cb_kernel_ivb, > > > - desc_count); > > > - gen7_emit_pipeline_flush(&cmds); > > > + descriptors = gen7_fill_interface_descriptor(&state, bv, > > > + IS_HASWELL(i915) ? > > > + &cb_kernel_hsw : > > > + &cb_kernel_ivb, > > > + desc_count); > > > + > > > + gen7_emit_pipeline_invalidate(&cmds); > > > batch_add(&cmds, PIPELINE_SELECT | PIPELINE_SELECT_MEDIA); > > > batch_add(&cmds, MI_NOOP); > > > - gen7_emit_state_base_address(&cmds, interface_descriptor); > > > + gen7_emit_pipeline_invalidate(&cmds); > > > + > > > gen7_emit_pipeline_flush(&cmds); > > > + gen7_emit_state_base_address(&cmds, descriptors); > > > + gen7_emit_pipeline_invalidate(&cmds); > > > > why do we need double invalidate? > > Empirical results. We need the flush before STATE_BASE otherwise there > were lost writes; mesa has had a similar experience with needing a > magical flush before. The invalidate afterwards is similarly required by > the HW. > > The invalidate before the PIPELINE_SELECT is mandatory in bspec for MEDIA, > and vouched for by our CI results. The one after the PIPELINE_SELECT does > not appear in the docs, yet preferred by CI. > > It's this combination of flush/invalidate that finally worked on all > three gen7 platforms, but there's almost definitely a more optimal set of > pipecontrols. okay. Let's move with this then. Better than reverting all the mitigation fix and we get something that unblocks users. Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > -Chris Thanks for all the clarifications, Rodrigo.
