iris: make BATCH_SZ smaller by BATCH_RESERVED bytes

[mesa.git] / src / gallium / drivers / iris / iris_batch.h

diff --git a/src/gallium/drivers/iris/iris_batch.h b/src/gallium/drivers/iris/iris_batch.h
index d8399d3cd34adcd6d32e70257f2340f75422b9ac..056a2469191c58a0a04dcd0cf36793821b97b4dd 100644 (file)
--- a/src/gallium/drivers/iris/iris_batch.h
+++ b/src/gallium/drivers/iris/iris_batch.h
@@ -38,8 +38,14 @@
 /* The kernel assumes batchbuffers are smaller than 256kB. */
 #define MAX_BATCH_SIZE (256 * 1024)
 
+/* Terminating the batch takes either 4 bytes for MI_BATCH_BUFFER_END
+ * or 12 bytes for MI_BATCH_BUFFER_START (when chaining).  Plus, we may
+ * need an extra 4 bytes to pad out to the nearest QWord.  So reserve 16.
+ */
+#define BATCH_RESERVED 16
+
 /* Our target batch size - flush approximately at this point. */
-#define BATCH_SZ (64 * 1024)
+#define BATCH_SZ (64 * 1024 - BATCH_RESERVED)
 
 enum iris_batch_name {
    IRIS_BATCH_RENDER,