sna: Improve handling of inplace IO for large transfers

If the transfer is large enough to obliterate the caches, then it is
preferrable to do it inplace rather than upload a proxy texture and
queue a blit. This helps prevent an inconsistency where one layer
believes the operation should be done inplace only for the IO layer to
perform an indirect upload.

Testing show no significant impact upon the cairo-traces, but it does
prevent x11perf -shmput from exploding.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 5 deletions

diff --git a/src/sna/sna_io.c b/src/sna/sna_io.c
index 2539518b..7cec3ff2 100644
--- a/src/sna/sna_io.c
+++ b/src/sna/sna_io.c
@@ -516,17 +516,16 @@ static bool upload_inplace(struct kgem *kgem,
 	 * able to almagamate a series of small writes into a single
 	 * operation.
 	 */
-	if (!bo->map) {
+	if (!bo->map || kgem_bo_map_will_stall(kgem, bo)) {
 		unsigned int bytes = 0;
 		while (n--) {
 			bytes += (box->x2 - box->x1) * (box->y2 - box->y1);
 			box++;
 		}
-		if (bytes * bpp >> 12 < kgem->half_cpu_cache_pages)
-			return false;
+		return bytes * bpp >> 12 >= kgem->half_cpu_cache_pages;
 	}
 
-	return !kgem_bo_map_will_stall(kgem, bo);
+	return true;
 }
 
 bool sna_write_boxes(struct sna *sna, PixmapPtr dst,
@@ -570,7 +569,9 @@ fallback:
 	}
 
 	/* Try to avoid switching rings... */
-	if (!can_blt || kgem->ring == KGEM_RENDER ||
+	if (!can_blt ||
+	    kgem->ring == KGEM_RENDER ||
+	    (kgem->has_semaphores && kgem->mode == KGEM_NONE) ||
 	    upload_too_large(sna, extents.x2 - extents.x1, extents.y2 - extents.y1)) {
 		PixmapRec tmp;