st/xorg: render throttling in block handler

Similar to the classic swapbuffer throttling in GL drivers, put an
upper bound on the number of outstanding chunks of rendering the state
tracker can generate -- where calling the block handler denotes a
chunk.

Currently that number is set at around 4 "chunks", but could be
tweaked up or down.  If a better measure for the amount of outstanding
rendering is found, that would be fine too.

As it stands, this improves interactivity by preventing the X server
from queueing up arbitary amounts of rendering.

diff --git a/src/gallium/state_trackers/xorg/xorg_driver.c b/src/gallium/state_trackers/xorg/xorg_driver.c
index c74fb28072972536c73a763f2ee2c2e2fe306358..4c66354ad450fa88b37d4a7c73107f59ef2c3847 100644 (file)
--- a/src/gallium/state_trackers/xorg/xorg_driver.c
+++ b/src/gallium/state_trackers/xorg/xorg_driver.c
@@ -450,8 +450,24 @@ static void drv_block_handler(int i, pointer blockData, pointer pTimeout,
     pScreen->BlockHandler(i, blockData, pTimeout, pReadmask);
     pScreen->BlockHandler = drv_block_handler;
 
-    if (ms->ctx)
-       ms->ctx->flush(ms->ctx, PIPE_FLUSH_RENDER_CACHE, NULL);
+    if (ms->ctx) {
+       int j;
+
+       ms->ctx->flush(ms->ctx, PIPE_FLUSH_RENDER_CACHE, &ms->fence[XORG_NR_FENCES-1]);
+       
+       if (ms->fence[0])
+          ms->ctx->screen->fence_finish(ms->ctx->screen, ms->fence[0], 0);
+  
+       /* The amount of rendering generated by a block handler can be
+        * quite small.  Let us get a fair way ahead of hardware before
+        * throttling.
+        */
+       for (j = 0; j < XORG_NR_FENCES; j++)
+          ms->screen->fence_reference(ms->screen,
+                                      &ms->fence[j],
+                                      ms->fence[j+1]);
+    }
+        
 
 #ifdef DRM_MODE_FEATURE_DIRTYFB
     {

diff --git a/src/gallium/state_trackers/xorg/xorg_renderer.c b/src/gallium/state_trackers/xorg/xorg_renderer.c
index 16ac5d204d9c1c70d15e4568cbcb70882f6ea04f..d9698e32e1fa74012b651bb11d45499d6e124c19 100644 (file)
--- a/src/gallium/state_trackers/xorg/xorg_renderer.c
+++ b/src/gallium/state_trackers/xorg/xorg_renderer.c
@@ -13,11 +13,6 @@
 
 #include <math.h>
 
-enum AxisOrientation {
-   Y0_BOTTOM,
-   Y0_TOP
-};
-
 #define floatsEqual(x, y) (fabs(x - y) <= 0.00001f * MIN2(fabs(x), fabs(y)))
 #define floatIsZero(x) (floatsEqual((x) + 1, 1))
 

diff --git a/src/gallium/state_trackers/xorg/xorg_tracker.h b/src/gallium/state_trackers/xorg/xorg_tracker.h
index 31e11b480932639d6e34ebb30f7b3771bb2e797e..c6c7b2fe158d6931291b8822068fc27b5cbfe300 100644 (file)
--- a/src/gallium/state_trackers/xorg/xorg_tracker.h
+++ b/src/gallium/state_trackers/xorg/xorg_tracker.h
@@ -63,6 +63,8 @@ typedef struct
     ScrnInfoPtr pScrn_2;
 } EntRec, *EntPtr;
 
+#define XORG_NR_FENCES 3
+
 typedef struct _modesettingRec
 {
     /* drm */
@@ -86,6 +88,8 @@ typedef struct _modesettingRec
     unsigned int SaveGeneration;
 
     void (*blockHandler)(int, pointer, pointer, pointer);
+    struct pipe_fence_handle *fence[XORG_NR_FENCES];
+
     CreateScreenResourcesProcPtr createScreenResources;
 
     /* for frontbuffer backing store */