[intel] Add a driconf option to cache freed buffer objects for reuse.

This is defaulted off as it has potentially large memory costs for a modest
performance gain.  Ideally we will improve DRM performance to the point where
this optimization is not worth the memory cost in any case, or find some
middle ground in caching only limited numbers of certain buffers.  For now,
this provides a modest 4% improvement in openarena on GM965 and 10% in openarena
on GM945.

1 files changed, 13 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
index d3f0681807..6c8ab1fa1e 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -456,6 +456,7 @@ intel_init_bufmgr(struct intel_context *intel)
        ttm_supported = GL_FALSE;
 
    if (!ttm_disable && ttm_supported) {
+      int bo_reuse_mode;
       intel->bufmgr = intel_bufmgr_ttm_init(intel->driFd,
 					    DRM_FENCE_TYPE_EXE,
 					    DRM_FENCE_TYPE_EXE |
@@ -463,6 +464,15 @@ intel_init_bufmgr(struct intel_context *intel)
 					    BATCH_SZ);
       if (intel->bufmgr != NULL)
 	 intel->ttm = GL_TRUE;
+
+      bo_reuse_mode = driQueryOptioni(&intel->optionCache, "bo_reuse");
+      switch (bo_reuse_mode) {
+      case DRI_CONF_BO_REUSE_DISABLED:
+	 break;
+      case DRI_CONF_BO_REUSE_ALL:
+	 intel_ttm_enable_bo_reuse(intel->bufmgr);
+	 break;
+      }
    }
    /* Otherwise, use the classic buffer manager. */
    if (intel->bufmgr == NULL) {
@@ -548,6 +558,9 @@ intelInitContext(struct intel_context *intel,
    intel->width = intelScreen->width;
    intel->height = intelScreen->height;
 
+   driParseConfigFiles(&intel->optionCache, &intelScreen->optionCache,
+                       intel->driScreen->myNum,
+		       IS_965(intelScreen->deviceID) ? "i965" : "i915");
    if (intelScreen->deviceID == PCI_CHIP_I865_G)
       intel->maxBatchSize = 4096;
    else
@@ -556,10 +569,6 @@ intelInitContext(struct intel_context *intel,
    if (!intel_init_bufmgr(intel))
       return GL_FALSE;
 
-   driParseConfigFiles(&intel->optionCache, &intelScreen->optionCache,
-                       intel->driScreen->myNum,
-		       IS_965(intelScreen->deviceID) ? "i965" : "i915");
-
    ctx->Const.MaxTextureMaxAnisotropy = 2.0;
 
    /* This doesn't yet catch all non-conformant rendering, but it's a