Let's try not waiting for the GuC WQ to be not-full, but instead
* count how many times this happens
* print a WARNING, at least sometimes
* return -EAGAIN
and see whether the GuC is ever a bottleneck for submission.
.Dave.
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_debugfs.c | 1 +
drivers/gpu/drm/i915/i915_guc_submission.c | 37 ++++++++++++++----------------
drivers/gpu/drm/i915/intel_guc.h | 8 +++----
3 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4950d05..d530fba 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2501,6 +2501,7 @@ static void i915_guc_client_info(struct seq_file *m,
seq_printf(m, "\tWQ size %d, offset: 0x%x, tail %d\n",
client->wq_size, client->wq_offset, client->wq_tail);
+ seq_printf(m, "\tWork queue full: %u\n", client->no_wq_space);
seq_printf(m, "\tFailed to queue: %u\n", client->q_fail);
seq_printf(m, "\tFailed doorbell: %u\n", client->b_fail);
seq_printf(m, "\tLast submission result: %d\n", client->retcode);
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index dc40a58..595b5e8 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -453,32 +453,29 @@ static void guc_fini_ctx_desc(struct intel_guc *guc,
int i915_guc_wq_check_space(struct drm_i915_gem_request *request)
{
- const size_t size = sizeof(struct guc_wq_item);
+ const size_t wqi_size = sizeof(struct guc_wq_item);
struct i915_guc_client *gc = request->i915->guc.execbuf_client;
struct guc_process_desc *desc;
- int ret = -ETIMEDOUT, timeout_counter = 200;
if (!gc)
return 0;
desc = gc->client_base + gc->proc_desc_offset;
- while (timeout_counter-- > 0) {
- if (CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size) >= size) {
- ret = 0;
- break;
- }
+ if (CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size) >= wqi_size)
+ return 0;
- if (timeout_counter)
- usleep_range(1000, 2000);
- };
+ /* A one-in-a-million chance? */
+ WARN(gc->no_wq_space % 0x100000 == 0, "GuC WQ full!");
+ gc->no_wq_space += 1;
- return ret;
+ return -EAGAIN;
}
static int guc_add_workqueue_item(struct i915_guc_client *gc,
struct drm_i915_gem_request *rq)
{
+ const size_t wqi_size = sizeof(struct guc_wq_item);
struct guc_process_desc *desc;
struct guc_wq_item *wqi;
void *base;
@@ -489,11 +486,6 @@ static int guc_add_workqueue_item(struct i915_guc_client *gc,
if (WARN_ON(space < sizeof(struct guc_wq_item)))
return -ENOSPC; /* shouldn't happen */
- /* postincrement WQ tail for next time */
- wq_off = gc->wq_tail;
- gc->wq_tail += sizeof(struct guc_wq_item);
- gc->wq_tail &= gc->wq_size - 1;
-
/* 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
* wrapped to the beginning. This simplifies the implementation below.
@@ -501,8 +493,13 @@ static int guc_add_workqueue_item(struct i915_guc_client *gc,
* XXX: if not the case, we need save data to a temp wqi and copy it to
* workqueue buffer dw by dw.
*/
- WARN_ON(sizeof(struct guc_wq_item) != 16);
- WARN_ON(wq_off & 3);
+ BUILD_BUG_ON(wqi_size != 16);
+
+ /* postincrement WQ tail for next time */
+ wq_off = gc->wq_tail;
+ WARN_ON(wq_off & (wqi_size - 1));
+ gc->wq_tail += wqi_size;
+ gc->wq_tail &= gc->wq_size - 1;
/* wq starts from the page after doorbell / process_desc */
base = kmap_atomic(i915_gem_object_get_page(gc->client_obj,
@@ -510,8 +507,8 @@ static int guc_add_workqueue_item(struct i915_guc_client *gc,
wq_off &= PAGE_SIZE - 1;
wqi = (struct guc_wq_item *)((char *)base + wq_off);
- /* len does not include the header */
- wq_len = sizeof(struct guc_wq_item) / sizeof(u32) - 1;
+ /* len is in DWords, and does not include the one-word header */
+ wq_len = wqi_size/sizeof(u32) - 1;
wqi->header = WQ_TYPE_INORDER |
(wq_len << WQ_LEN_SHIFT) |
(rq->engine->guc_id << WQ_TARGET_SHIFT) |
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index a5cd4af..84e8593 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -73,10 +73,10 @@ struct i915_guc_client {
/* GuC submission statistics & status */
uint64_t submissions[GUC_MAX_ENGINES_NUM];
- uint32_t q_fail;
- uint32_t b_fail;
- int retcode;
- int spare; /* pad to 32 DWords */
+ uint32_t no_wq_space; /* Space pre-check failed */
+ uint32_t q_fail; /* Failed to queue (MBZ) */
+ uint32_t b_fail; /* Doorbell failure (MBZ) */
+ int retcode; /* Result of last guc_submit() */
};
enum intel_guc_fw_status {
--
1.9.1
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