[PATCH 12/18] drm/i915: Increase GuC log buffer size to reduce flush interrupts

akash.goel
2016-08-15T14:36:39Z

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

In cases where GuC generate logs at a very high rate, correspondingly
the rate of flush interrupts is also very high.
So far total 8 pages were allocated for storing both ISR & DPC logs.
As per the half-full draining protocol followed by GuC, by doubling
the number of pages, the frequency of flush interrupts can be cut down
to almost half, which then helps in reducing the logging overhead.
So now allocating 8 pages apiece for ISR & DPC logs.
This also helps in reducing the output log file size, apart from
reducing the flush interrupt count. With the original settings,
44 KB was needed for one snapshot. With modified settings, 76 KB is
needed for a snapshot which will be equivalent to 2 snapshots of the
original setting. So 12KB saving, every 88 KB, over the original setting.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/intel_guc_fwif.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_fwif.h b/drivers/gpu/drm/i915/intel_guc_fwif.h
index 47ef7e8..49dbe25 100644
--- a/drivers/gpu/drm/i915/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/intel_guc_fwif.h
@@ -104,9 +104,9 @@
#define GUC_LOG_ALLOC_IN_MEGABYTE (1 << 3)
#define GUC_LOG_CRASH_PAGES 1
#define GUC_LOG_CRASH_SHIFT 4
-#define GUC_LOG_DPC_PAGES 3
+#define GUC_LOG_DPC_PAGES 7
#define GUC_LOG_DPC_SHIFT 6
-#define GUC_LOG_ISR_PAGES 3
+#define GUC_LOG_ISR_PAGES 7
#define GUC_LOG_ISR_SHIFT 9
#define GUC_LOG_BUF_ADDR_SHIFT 12

@@ -436,9 +436,9 @@ enum guc_log_buffer_type {
* | Crash dump state header |
* Page1 +-------------------------------+
* | ISR logs |
- * Page5 +-------------------------------+
- * | DPC logs |
* Page9 +-------------------------------+
+ * | DPC logs |
+ * Page17 +-------------------------------+
* | Crash Dump logs |
* +-------------------------------+
*
--
1.9.2