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

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 12/08/16 07:25, akash.goel@intel.com wrote:
> From: Akash Goel <akash.goel@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@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]);

Why is the width for overflow only 8 chars and not 10 like for flush 
since both are u32?

> +
> +	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 {
>

Either if the formatting widths above are fine or you adjust them:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko


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