intel/fs: Add a parameter to speed up register spilling

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24299>

diff --git a/src/intel/compiler/brw_compiler.h b/src/intel/compiler/brw_compiler.h
index f0fcf83..e373d02 100644 (file)
--- a/src/intel/compiler/brw_compiler.h
+++ b/src/intel/compiler/brw_compiler.h
@@ -128,6 +128,15 @@ struct brw_compiler {
     */
    bool use_bindless_sampler_offset;
 
+   /**
+    * Calling the ra_allocate function after each register spill can take
+    * several minutes. This option speeds up shader compilation by spilling
+    * more registers after the ra_allocate failure. Required for
+    * Cyberpunk 2077, which uses a watchdog thread to terminate the process
+    * in case the render thread hasn't responded within 2 minutes.
+    */
+   int spilling_rate;
+
    struct nir_shader *clc_shader;
 
    struct {

diff --git a/src/intel/compiler/brw_fs_reg_allocate.cpp b/src/intel/compiler/brw_fs_reg_allocate.cpp
index 9a6fe4d..3b71a1d 100644 (file)
--- a/src/intel/compiler/brw_fs_reg_allocate.cpp
+++ b/src/intel/compiler/brw_fs_reg_allocate.cpp
@@ -1308,7 +1308,7 @@ fs_reg_alloc::assign_regs(bool allow_spilling, bool spill_all)
 {
    build_interference_graph(fs->spilled_any_registers || spill_all);
 
-   bool spilled = false;
+   unsigned spilled = 0;
    while (1) {
       /* Debug of register spilling: Go spill everything. */
       if (unlikely(spill_all)) {
@@ -1325,24 +1325,33 @@ fs_reg_alloc::assign_regs(bool allow_spilling, bool spill_all)
       if (!allow_spilling)
          return false;
 
-      /* Failed to allocate registers.  Spill a reg, and the caller will
+      /* Failed to allocate registers.  Spill some regs, and the caller will
        * loop back into here to try again.
        */
-      int reg = choose_spill_reg();
-      if (reg == -1)
-         return false;
+      unsigned nr_spills = 1;
+      if (compiler->spilling_rate)
+         nr_spills = MAX2(1, spilled / compiler->spilling_rate);
 
-      /* If we're going to spill but we've never spilled before, we need to
-       * re-build the interference graph with MRFs enabled to allow spilling.
-       */
-      if (!fs->spilled_any_registers) {
-         discard_interference_graph();
-         build_interference_graph(true);
-      }
+      for (unsigned j = 0; j < nr_spills; j++) {
+         int reg = choose_spill_reg();
+         if (reg == -1) {
+            if (j == 0)
+               return false; /* Nothing to spill */
+            break;
+         }
 
-      spilled = true;
+         /* If we're going to spill but we've never spilled before, we need
+          * to re-build the interference graph with MRFs enabled to allow
+          * spilling.
+          */
+         if (!fs->spilled_any_registers) {
+            discard_interference_graph();
+            build_interference_graph(true);
+         }
 
-      spill_reg(reg);
+         spill_reg(reg);
+         spilled++;
+      }
    }
 
    if (spilled)