[Mesa-dev] [PATCH] i965: Avoids loop for buffer object availability in add_exec_bo

[aravindan.muthukumar at intel.com]

From: Aravindan Muthukumar <aravindan.muthukumar at intel.com>

Original logic loops over the list for every buffer object. Maintained
a flag to identify whether bo is already there in list.

Improves performance - 3DMark by 2%
Tested with piglit

Signed-off-by: Aravindan Muthukumar <aravindan.muthukumar at intel.com>
Signed-off-by: Yogesh Marathe <yogesh.marathe at intel.com>
---
 src/mesa/drivers/dri/i965/brw_bufmgr.h        |  5 +++++
 src/mesa/drivers/dri/i965/intel_batchbuffer.c | 24 +++++++++++++++---------
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.h b/src/mesa/drivers/dri/i965/brw_bufmgr.h
index 6a6051b..912ffb0 100644
--- a/src/mesa/drivers/dri/i965/brw_bufmgr.h
+++ b/src/mesa/drivers/dri/i965/brw_bufmgr.h
@@ -132,6 +132,11 @@ struct brw_bo {
     * Boolean of whether this buffer is cache coherent
     */
    bool cache_coherent;
+
+   /**
+     * Boolean to check whether bo is available in exec buffer objects list
+     */
+   bool bo_available;
 };
 
 #define BO_ALLOC_FOR_RENDER (1<<0)
diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
index e2f208a..0814e8b 100644
--- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
+++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
@@ -513,10 +513,8 @@ static void
 add_exec_bo(struct intel_batchbuffer *batch, struct brw_bo *bo)
 {
    if (bo != batch->bo) {
-      for (int i = 0; i < batch->exec_count; i++) {
-         if (batch->exec_bos[i] == bo)
-            return;
-      }
+      if(brw_batch_references(batch,bo) == true)
+         return;
 
       brw_bo_reference(bo);
    }
@@ -548,6 +546,12 @@ add_exec_bo(struct intel_batchbuffer *batch, struct brw_bo *bo)
    validation_entry->rsvd2 = 0;
 
    batch->exec_bos[batch->exec_count] = bo;
+
+   /* Marking the current bo as true since this
+    * is added to the exec_bos list
+    */
+   bo->bo_available = true;
+
    batch->exec_count++;
    batch->aperture_space += bo->size;
 }
@@ -592,6 +596,12 @@ execbuffer(int fd,
 
       bo->idle = false;
 
+      /* Marking the flags as false for all the bo's
+       * in the list to ensure it is added in the next
+       * list of exec buffers
+       */
+      bo->bo_available = false;
+
       /* Update brw_bo::offset64 */
       if (batch->validation_list[i].offset != bo->offset64) {
          DBG("BO %d migrated: 0x%" PRIx64 " -> 0x%llx\n",
@@ -736,11 +746,7 @@ brw_batch_has_aperture_space(struct brw_context *brw, unsigned extra_space)
 bool
 brw_batch_references(struct intel_batchbuffer *batch, struct brw_bo *bo)
 {
-   for (int i = 0; i < batch->exec_count; i++) {
-      if (batch->exec_bos[i] == bo)
-         return true;
-   }
-   return false;
+   return (bo->bo_available) ? true : false;
 }
 
 /*  This is the only way buffers get added to the validate list.
-- 
2.7.4