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 <[email protected]> Cc: Daniele Ceraolo Spurio <[email protected]> Cc: Michal Wajdeczko <[email protected]> Cc: Oscar Mateo <[email protected]> Suggested-by: Chris Wilson <[email protected]> Signed-off-by: Michał Winiarski <[email protected]> --- 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 f5fd00cfb3b0..e124e91aefcf 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, cookie 0x%x\n", client->doorbell_id, client->doorbell_offset, client->doorbell_cookie); - 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 6f0adcd2a058..3a8a77ae2af8 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -306,7 +306,7 @@ 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; } @@ -391,8 +391,8 @@ 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; } @@ -416,15 +416,15 @@ 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 @@ -435,11 +435,12 @@ 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; @@ -453,7 +454,7 @@ 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; } @@ -463,20 +464,14 @@ static void guc_reset_wq(struct i915_guc_client *client) desc->head = 0; desc->tail = 0; - - client->wq_tail = 0; } static int guc_ring_doorbell(struct i915_guc_client *client) { - struct guc_process_desc *desc = __get_process_desc(client); union guc_doorbell_qw db_cmp, db_exc, db_ret; union guc_doorbell_qw *db; int attempt = 2, ret = -EAGAIN; - /* Update the tail so it is visible to GuC */ - desc->tail = client->wq_tail; - /* current cookie */ db_cmp.db_status = GUC_DOORBELL_ENABLED; db_cmp.cookie = client->doorbell_cookie; @@ -535,7 +530,6 @@ 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; @@ -548,14 +542,10 @@ 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); WARN_ON(guc_ring_doorbell(client)); client->submissions[engine_id] += 1; - - spin_unlock_irqrestore(&client->wq_lock, flags); } } } @@ -848,9 +838,6 @@ 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 d41051688221..851b4f173781 100644 --- a/drivers/gpu/drm/i915/intel_uc.h +++ b/drivers/gpu/drm/i915/intel_uc.h @@ -68,11 +68,6 @@ struct i915_guc_client { unsigned long doorbell_offset; u32 doorbell_cookie; - 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]; }; -- 2.13.5 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
