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, 36 insertions, 17 deletions

diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_cs.h b/src/gallium/winsys/radeon/drm/radeon_drm_cs.h
index 0183b877a3..486fd237fc 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_cs.h
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_cs.h
@@ -30,34 +30,53 @@
 #include "radeon_drm_bo.h"
 #include <radeon_drm.h>
 
-struct radeon_drm_cs {
-    struct r300_winsys_cs base;
-
-    /* The winsys. */
-    struct radeon_drm_winsys *ws;
+struct radeon_cs_context {
+    uint32_t                    buf[R300_MAX_CMDBUF_DWORDS];
 
-    /* Flush CS. */
-    void (*flush_cs)(void *);
-    void *flush_data;
+    int fd;
+    struct drm_radeon_cs        cs;
+    struct drm_radeon_cs_chunk  chunks[2];
+    uint64_t                    chunk_array[2];
 
     /* Relocs. */
-    unsigned                    crelocs;
     unsigned                    nrelocs;
-    struct drm_radeon_cs_reloc  *relocs;
+    unsigned                    crelocs;
     struct radeon_bo            **relocs_bo;
-    struct drm_radeon_cs        cs;
-    struct drm_radeon_cs_chunk  chunks[2];
-
-    unsigned used_vram;
-    unsigned used_gart;
+    struct drm_radeon_cs_reloc  *relocs;
 
     /* 0 = BO not added, 1 = BO added */
     char                        is_handle_added[256];
     struct drm_radeon_cs_reloc  *relocs_hashlist[256];
     unsigned                    reloc_indices_hashlist[256];
+
+    unsigned used_vram;
+    unsigned used_gart;
+};
+
+struct radeon_drm_cs {
+    struct r300_winsys_cs base;
+
+    /* We flip between these two CS. While one is being consumed
+     * by the kernel in another thread, the other one is being filled
+     * by the pipe driver. */
+    struct radeon_cs_context csc1;
+    struct radeon_cs_context csc2;
+    /* The currently-used CS. */
+    struct radeon_cs_context *csc;
+    /* The CS being currently-owned by the other thread. */
+    struct radeon_cs_context *cst;
+
+    /* The winsys. */
+    struct radeon_drm_winsys *ws;
+
+    /* Flush CS. */
+    void (*flush_cs)(void *);
+    void *flush_data;
+
+    pipe_thread thread;
 };
 
-int radeon_get_reloc(struct radeon_drm_cs *cs, struct radeon_bo *bo);
+int radeon_get_reloc(struct radeon_cs_context *csc, struct radeon_bo *bo);
 
 static INLINE struct radeon_drm_cs *
 radeon_drm_cs(struct r300_winsys_cs *base)
@@ -69,7 +88,7 @@ static INLINE boolean radeon_bo_is_referenced_by_cs(struct radeon_drm_cs *cs,
                                                     struct radeon_bo *bo)
 {
     return bo->num_cs_references == bo->rws->num_cs ||
-           (bo->num_cs_references && radeon_get_reloc(cs, bo) != -1);
+           (bo->num_cs_references && radeon_get_reloc(cs->csc, bo) != -1);
 }
 
 static INLINE boolean radeon_bo_is_referenced_by_any_cs(struct radeon_bo *bo)