From: Aravindan Muthukumar <aravindan.muthuku...@intel.com>
Avoiding the loop which was running with O(n) complexity.
Now the complexity has been reduced to O(1)
Tested with piglit.
Slight performance improvement (~1%) in 3d mark.
Change-Id: Id099f1cd24ad5b691a69070eda79b8f4e9be39a6
Signed-off-by: Aravindan Muthukumar <aravindan.muthuku...@intel.com>
Signed-off-by: Kedar Karanje <kedar.j.kara...@intel.com>
Reviewed-by: Yogesh Marathe <yogesh.mara...@intel.com>
---
src/mesa/drivers/dri/i965/brw_bufmgr.c | 48 +++++++++++++++++++++++++++++-----
1 file changed, 41 insertions(+), 7 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c
b/src/mesa/drivers/dri/i965/brw_bufmgr.c
index 5b4e784..18cb166 100644
--- a/src/mesa/drivers/dri/i965/brw_bufmgr.c
+++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c
@@ -87,6 +87,11 @@
#define memclear(s) memset(&s, 0, sizeof(s))
+/* Macros for BO cache size */
+#define CACHE_PAGE_SIZE 4096
+#define PAGE_SIZE_SHIFT 12
+#define BO_CACHE_PAGE_SIZE (4 * CACHE_PAGE_SIZE)
+
#define FILE_DEBUG_FLAG DEBUG_BUFMGR
static inline int
@@ -181,19 +186,48 @@ bo_tile_pitch(struct brw_bufmgr *bufmgr, uint32_t pitch,
uint32_t tiling)
return ALIGN(pitch, tile_width);
}
+/*
+ * This functions is to find the correct bucket fit for the input size.
+ * This function works with O(1) complexity when the requested size
+ * was queried instead of iterating the size through all the buckets.
+ */
static struct bo_cache_bucket *
bucket_for_size(struct brw_bufmgr *bufmgr, uint64_t size)
{
- int i;
+ struct bo_cache_bucket *bucket = NULL;
+ int x=0,index = -1;
+ int row, col=0;
- for (i = 0; i < bufmgr->num_buckets; i++) {
- struct bo_cache_bucket *bucket = &bufmgr->cache_bucket[i];
- if (bucket->size >= size) {
- return bucket;
- }
+ /* condition for size less than 4*4096 (4KB) page size */
+ if(size < BO_CACHE_PAGE_SIZE){
+ index = (size>>PAGE_SIZE_SHIFT)+((size%(1<<PAGE_SIZE_SHIFT)?1:0))-1;
}
+ else{
+ /* When the size is more than 4*4096, the logic follows a matrix method
+ * where the index will be searched using Arithmetico-Geometric
progression.
+ * So the given size will be divided by 4096 & the index will be traced
out.
+ */
+ x = size>>PAGE_SIZE_SHIFT;
- return NULL;
+ /* Find the row using Geometric Progression. The highest bit set will
give
+ * the row number. num = a * r^(n-1) where num = size a = 4 r = 2
+ */
+ row = 31 - __builtin_clz(x>>1);
+
+ /* Find the column using AP but using the row value
+ * calculated using GP.
+ */
+ col =((x-(1<<(row+1)))/(1<<(row-1)))+1;
+ col += (size%(1<<PAGE_SIZE_SHIFT<<(row-1)))?1:0;
+
+ /* Finding the index value using calculated row and col number */
+ index = ((row-1)<<2) + col + 2;
+ }
+
+ /* Checking the error condition */
+ bucket = (index >= 0 && index <
bufmgr->num_buckets)?(&bufmgr->cache_bucket[index]):NULL;
+ return bucket;
}
int
--
2.7.4
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