serialize simulator on wfi

This improves simulator perf when a thread is idle, or waiting on HTIF.

diff --git a/riscv/decode.h b/riscv/decode.h
index b607bf38a02daccce1b90daafa71b89eb38a8c4c..d82767deecacd61879b56925773b843980dee5c9 100644 (file)
--- a/riscv/decode.h
+++ b/riscv/decode.h
@@ -202,9 +202,10 @@ private:
      } while(0)
 
 #define set_pc_and_serialize(x) \
-  do { set_pc(x); /* check alignment */ \
+  do { reg_t __npc = (x); \
+       set_pc(__npc); /* check alignment */ \
        npc = PC_SERIALIZE_AFTER; \
-       STATE.pc = (x); \
+       STATE.pc = __npc; \
      } while(0)
 
 /* Sentinel PC values to serialize simulator pipeline */

diff --git a/riscv/execute.cc b/riscv/execute.cc
index ebc9dc7e79e12474e4a6735d248a2d2a9fb85103..1b53ccf7c3e4eeff9dfcf426f3b3024d5f354d99 100644 (file)
--- a/riscv/execute.cc
+++ b/riscv/execute.cc
@@ -84,7 +84,7 @@ void processor_t::step(size_t n)
      if (unlikely(invalid_pc(pc))) { \
        switch (pc) { \
          case PC_SERIALIZE_BEFORE: state.serialized = true; break; \
-         case PC_SERIALIZE_AFTER: instret++; break; \
+         case PC_SERIALIZE_AFTER: n = ++instret; break; \
          default: abort(); \
        } \
        pc = state.pc; \

diff --git a/riscv/insns/wfi.h b/riscv/insns/wfi.h
index 6f037f8a9c689c7b5df689470d60c1f0b9e80427..643c3747cda991997651b8294d96021abeda159b 100644 (file)
--- a/riscv/insns/wfi.h
+++ b/riscv/insns/wfi.h
@@ -1 +1 @@
-// nop
+set_pc_and_serialize(npc);