From: Michał Winiarski <michal.winiarski@xxxxxxxxx> We can get rid of a spinlock by updating the tail directly using cmpxchg. We can also put guc client on a diet by removing some constants from the struct. This causes a small change in one of GuC debugfs files. We're no longer reporting constant values (which I don't think is a problem), but we're also no longer reporting the tail (does anyone care?). Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx> Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx> Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20170912124726.19689-3-michal.winiarski@xxxxxxxxx --- drivers/gpu/drm/i915/i915_debugfs.c | 2 -- drivers/gpu/drm/i915/i915_guc_submission.c | 39 ++++++++++-------------------- drivers/gpu/drm/i915/intel_uc.h | 5 ---- 3 files changed, 13 insertions(+), 33 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 40a315fc0e31..0bd5cacd288b 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -2447,8 +2447,6 @@ static void i915_guc_client_info(struct seq_file *m, client->priority, client->stage_id, client->proc_desc_offset); seq_printf(m, "\tDoorbell id %d, offset: 0x%lx\n", client->doorbell_id, client->doorbell_offset); - seq_printf(m, "\tWQ size %d, offset: 0x%x, tail %d\n", - client->wq_size, client->wq_offset, client->wq_tail); for_each_engine(engine, dev_priv, id) { u64 submissions = client->submissions[id]; diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index d6f3a1837a2d..f4da655c7275 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -305,7 +305,7 @@ static void guc_proc_desc_init(struct intel_guc *guc, desc->db_base_addr = 0; desc->stage_id = client->stage_id; - desc->wq_size_bytes = client->wq_size; + desc->wq_size_bytes = GUC_WQ_SIZE; desc->wq_status = WQ_STATUS_ACTIVE; desc->priority = client->priority; } @@ -390,8 +390,8 @@ static void guc_stage_desc_init(struct intel_guc *guc, desc->db_trigger_cpu = (uintptr_t)__get_doorbell(client); desc->db_trigger_uk = gfx_addr + client->doorbell_offset; desc->process_desc = gfx_addr + client->proc_desc_offset; - desc->wq_addr = gfx_addr + client->wq_offset; - desc->wq_size = client->wq_size; + desc->wq_addr = gfx_addr + GUC_DB_SIZE; + desc->wq_size = GUC_WQ_SIZE; desc->desc_private = (uintptr_t)client; } @@ -415,15 +415,15 @@ static void guc_wq_item_append(struct i915_guc_client *client, struct intel_engine_cs *engine = rq->engine; struct guc_process_desc *desc = __get_process_desc(client); struct guc_wq_item *wqi; - u32 freespace, tail, wq_off; + u32 freespace, ring_tail, wq_off, wq_next; /* Free space is guaranteed */ - freespace = CIRC_SPACE(client->wq_tail, desc->head, client->wq_size); + freespace = CIRC_SPACE(desc->tail, desc->head, GUC_WQ_SIZE); GEM_BUG_ON(freespace < wqi_size); /* The GuC firmware wants the tail index in QWords, not bytes */ - tail = intel_ring_set_tail(rq->ring, rq->tail) >> 3; - GEM_BUG_ON(tail > WQ_RING_TAIL_MAX); + ring_tail = intel_ring_set_tail(rq->ring, rq->tail) >> 3; + GEM_BUG_ON(ring_tail > WQ_RING_TAIL_MAX); /* For now workqueue item is 4 DWs; workqueue buffer is 2 pages. So we * should not have the case where structure wqi is across page, neither @@ -434,11 +434,12 @@ static void guc_wq_item_append(struct i915_guc_client *client, */ BUILD_BUG_ON(wqi_size != 16); - /* postincrement WQ tail for next time */ - wq_off = client->wq_tail; + /* Find our offset and postincrement WQ tail for next time */ + do { + wq_off = desc->tail; + wq_next = (wq_off + wqi_size) & (GUC_WQ_SIZE - 1); + } while (cmpxchg(&desc->tail, wq_off, wq_next) != wq_off); GEM_BUG_ON(wq_off & (wqi_size - 1)); - client->wq_tail += wqi_size; - client->wq_tail &= client->wq_size - 1; /* WQ starts from the page after doorbell / process_desc */ wqi = client->vaddr + wq_off + GUC_DB_SIZE; @@ -452,7 +453,7 @@ static void guc_wq_item_append(struct i915_guc_client *client, /* The GuC wants only the low-order word of the context descriptor */ wqi->context_desc = (u32)intel_lr_context_descriptor(rq->ctx, engine); - wqi->submit_element_info = tail << WQ_RING_TAIL_SHIFT; + wqi->submit_element_info = ring_tail << WQ_RING_TAIL_SHIFT; wqi->fence_id = rq->global_seqno; } @@ -462,19 +463,13 @@ static void guc_reset_wq(struct i915_guc_client *client) desc->head = 0; desc->tail = 0; - - client->wq_tail = 0; } static void guc_ring_doorbell(struct i915_guc_client *client) { - struct guc_process_desc *desc = __get_process_desc(client); struct guc_doorbell_info *db = __get_doorbell(client); u32 cookie; - /* Update the tail so it is visible to GuC */ - desc->tail = client->wq_tail; - do { cookie = READ_ONCE(db->cookie); } while (cmpxchg(&db->cookie, cookie, cookie + 1) != cookie); @@ -496,7 +491,6 @@ static void i915_guc_submit(struct intel_engine_cs *engine) struct execlist_port *port = engine->execlist_port; unsigned int engine_id = engine->id; unsigned int n; - unsigned long flags; for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++) { struct drm_i915_gem_request *rq; @@ -509,14 +503,10 @@ static void i915_guc_submit(struct intel_engine_cs *engine) if (i915_vma_is_map_and_fenceable(rq->ring->vma)) POSTING_READ_FW(GUC_STATUS); - spin_lock_irqsave(&client->wq_lock, flags); - guc_wq_item_append(client, rq); guc_ring_doorbell(client); client->submissions[engine_id] += 1; - - spin_unlock_irqrestore(&client->wq_lock, flags); } } } @@ -809,9 +799,6 @@ guc_client_alloc(struct drm_i915_private *dev_priv, client->engines = engines; client->priority = priority; client->doorbell_id = GUC_DOORBELL_INVALID; - client->wq_offset = GUC_DB_SIZE; - client->wq_size = GUC_WQ_SIZE; - spin_lock_init(&client->wq_lock); ret = ida_simple_get(&guc->stage_ids, 0, GUC_MAX_STAGE_DESCRIPTORS, GFP_KERNEL); diff --git a/drivers/gpu/drm/i915/intel_uc.h b/drivers/gpu/drm/i915/intel_uc.h index f505dcccd613..386e0bcd0cc3 100644 --- a/drivers/gpu/drm/i915/intel_uc.h +++ b/drivers/gpu/drm/i915/intel_uc.h @@ -67,11 +67,6 @@ struct i915_guc_client { u16 doorbell_id; unsigned long doorbell_offset; - spinlock_t wq_lock; - uint32_t wq_offset; - uint32_t wq_size; - uint32_t wq_tail; - /* Per-engine counts of GuC submissions */ uint64_t submissions[I915_NUM_ENGINES]; }; -- 2.14.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
