r300g: offload the CS ioctl to another thread

This is a multi-threading optimization which hides the kernel overhead
behind a thread. It improves performance in CPU-limited apps by 2-15%.
Of course you must have at least 2 cores for it to make any difference.

It can be disabled with:

export RADEON_THREAD=0

1 files changed, 4 insertions, 0 deletions

diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_bo.h b/src/gallium/winsys/radeon/drm/radeon_drm_bo.h
index d877512be5..a26866b7e7 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_bo.h
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_bo.h
@@ -59,6 +59,10 @@ struct radeon_bo {
     /* how many command streams is this bo referenced in? */
     int num_cs_references;
 
+    /* how many command streams, which are being emitted in a separate
+     * thread, is this bo referenced in? */
+    int num_active_ioctls;
+
     boolean flinked;
     uint32_t flink;
 };