[Intel-gfx] [PATCH 10/20] drm/i915: Add stats for GuC log buffer flush interrupts

[akash.goel at intel.com]

From: Akash Goel <akash.goel at intel.com>

GuC firmware sends an interrupt to flush the log buffer when it
becomes half full. GuC firmware also tracks how many times the
buffer overflowed.
It would be useful to maintain a statistics of how many flush
interrupts were received and for which type of log buffer,
along with the overflow count of each buffer type.
Augmented i915_log_info debugfs to report back these statistics.

v2:
- Update the logic to detect multiple overflows between the 2
  flush interrupts and also log a message for overflow (Tvrtko)
- Track the number of times there was no free sub buffer to capture
  the GuC log buffer. (Tvrtko)

Signed-off-by: Akash Goel <akash.goel at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c        | 28 ++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_guc_submission.c | 19 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_irq.c            |  2 ++
 drivers/gpu/drm/i915/intel_guc.h           |  7 +++++++
 4 files changed, 56 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 51b59d5..14e0dcf 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2539,6 +2539,32 @@ static int i915_guc_load_status_info(struct seq_file *m, void *data)
 	return 0;
 }
 
+static void i915_guc_log_info(struct seq_file *m,
+				 struct drm_i915_private *dev_priv)
+{
+	struct intel_guc *guc = &dev_priv->guc;
+
+	seq_printf(m, "\nGuC logging stats:\n");
+
+	seq_printf(m, "\tISR:   flush count %10u, overflow count %8u\n",
+		guc->log.flush_count[GUC_ISR_LOG_BUFFER],
+		guc->log.total_overflow_count[GUC_ISR_LOG_BUFFER]);
+
+	seq_printf(m, "\tDPC:   flush count %10u, overflow count %8u\n",
+		guc->log.flush_count[GUC_DPC_LOG_BUFFER],
+		guc->log.total_overflow_count[GUC_DPC_LOG_BUFFER]);
+
+	seq_printf(m, "\tCRASH: flush count %10u, overflow count %8u\n",
+		guc->log.flush_count[GUC_CRASH_DUMP_LOG_BUFFER],
+		guc->log.total_overflow_count[GUC_CRASH_DUMP_LOG_BUFFER]);
+
+	seq_printf(m, "\tTotal flush interrupt count: %u\n",
+		       guc->log.flush_interrupt_count);
+
+	seq_printf(m, "\tCapture miss count: %u\n",
+		       guc->log.capture_miss_count);
+}
+
 static void i915_guc_client_info(struct seq_file *m,
 				 struct drm_i915_private *dev_priv,
 				 struct i915_guc_client *client)
@@ -2613,6 +2639,8 @@ static int i915_guc_info(struct seq_file *m, void *data)
 	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc.execbuf_client);
 	i915_guc_client_info(m, dev_priv, &client);
 
+	i915_guc_log_info(m, dev_priv);
+
 	/* Add more as required ... */
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index cb9672b..1ca1866 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -913,6 +913,24 @@ static void guc_read_update_log_buffer(struct intel_guc *guc)
 				sizeof(struct guc_log_buffer_state));
 		buffer_size = log_buffer_state_local.size;
 
+		guc->log.flush_count[i] += log_buffer_state_local.flush_to_file;
+		if (log_buffer_state_local.buffer_full_cnt !=
+					guc->log.prev_overflow_count[i]) {
+			guc->log.total_overflow_count[i] +=
+				(log_buffer_state_local.buffer_full_cnt -
+				 guc->log.prev_overflow_count[i]);
+
+			if (log_buffer_state_local.buffer_full_cnt <
+					guc->log.prev_overflow_count[i]) {
+				/* buffer_full_cnt is a 4 bit counter */
+				guc->log.total_overflow_count[i] += 16;
+			}
+
+			guc->log.prev_overflow_count[i] =
+					log_buffer_state_local.buffer_full_cnt;
+			DRM_ERROR_RATELIMITED("GuC log buffer overflow\n");
+		}
+
 		if (log_buffer_snapshot_state) {
 			/* First copy the state structure in local buffer */
 			memcpy(log_buffer_snapshot_state, &log_buffer_state_local,
@@ -953,6 +971,7 @@ static void guc_read_update_log_buffer(struct intel_guc *guc)
 		 * getting consumed by User at a slow rate.
 		 */
 		DRM_ERROR_RATELIMITED("no sub-buffer to capture log buffer\n");
+		guc->log.capture_miss_count++;
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d4d6f0a..b08d1d2 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1705,6 +1705,8 @@ static void gen9_guc_irq_handler(struct drm_i915_private *dev_priv, u32 gt_iir)
 				/* Handle flush interrupt event in bottom half */
 				queue_work(dev_priv->guc.log.wq,
 						&dev_priv->guc.events_work);
+
+				dev_priv->guc.log.flush_interrupt_count++;
 			}
 		}
 	}
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index e4ec8d8..ed87e98 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -127,6 +127,13 @@ struct intel_guc_log {
 	struct workqueue_struct *wq;
 	void *buf_addr;
 	struct rchan *relay_chan;
+
+	/* logging related stats */
+	u32 capture_miss_count;
+	u32 flush_interrupt_count;
+	u32 prev_overflow_count[GUC_MAX_LOG_BUFFER];
+	u32 total_overflow_count[GUC_MAX_LOG_BUFFER];
+	u32 flush_count[GUC_MAX_LOG_BUFFER];
 };
 
 struct intel_guc {
-- 
1.9.2