Merge branch 'raptorjit/master' into auditlog

src/lj_asm.c

@@ -1953,6 +1953,23 @@ static void asm_setup_regsp(ASMState *as)
 
 /* -- Assembler core ------------------------------------------------------ */
 
+/* Do we want the profiler to attribute VM time to this trace?
+ *
+ * Not if the root of this trace is a Lua function. We assume that the
+ * root cause of running the interpreter is a loop that failed to
+ * compile somewhere and that entry/exit through function traces is
+ * only noise that should be filtered out.
+ *
+ * This helps the profiler to point out the code that needs to be
+ * changed to reduce time spent in the interpreter.
+ */
+static int asm_should_profile_exit(jit_State *J, GCtrace *T)
+{
+ GCtrace *root = traceref(J, T->root ? T->root : T->traceno);
+ BCOp op = bc_op(root->startins);
+ return op != BC_FUNCF && op != BC_FUNCV;
+}
+
 /* Assemble a trace. */
 void lj_asm_trace(jit_State *J, GCtrace *T)
 {
@@ -2107,7 +2124,8 @@ void lj_asm_trace(jit_State *J, GCtrace *T)
  T->mcode = as->mcp;
  T->mcloop = as->mcloop ? (MSize)((char *)as->mcloop - (char *)as->mcp) : 0;
  if (!as->loopref)
- asm_tail_fixup(as, T->link); /* Note: this may change as->mctop! */
+ /* Note: this may change as->mctop! */
+ asm_tail_fixup(as, T->link, asm_should_profile_exit(J, T));
  T->szmcode = (MSize)((char *)as->mctop - (char *)as->mcp);
  lj_mcode_sync(T->mcode, origtop);
 }

src/lj_asm_x86.h

@@ -2273,7 +2273,7 @@ static RegSet asm_head_side_base(ASMState *as, IRIns *irp, RegSet allow)
 /* -- Tail of trace ------------------------------------------------------- */
 
 /* Fixup the tail code. */
-static void asm_tail_fixup(ASMState *as, TraceNo lnk)
+static void asm_tail_fixup(ASMState *as, TraceNo lnk, int track)
 {
  /* Note: don't use as->mcp swap + emit_*: emit_op overwrites more bytes. */
  MCode *p = as->mctop;
@@ -2304,7 +2304,9 @@ static void asm_tail_fixup(ASMState *as, TraceNo lnk)
  }
  }
  /* Patch exit branch. */
- target = lnk ? traceref(as->J, lnk)->mcode : (MCode *)lj_vm_exit_interp;
+ target = (lnk ? traceref(as->J, lnk)->mcode :
+ (track ? (MCode *)lj_vm_exit_interp :
+ (MCode *)lj_vm_exit_interp_notrack));
  *(int32_t *)(p-4) = jmprel(p, target);
  p[-5] = XI_JMP;
  /* Drop unused mcode tail. Fill with NOPs to make the prefetcher happy. */

src/lj_vm.h

@@ -38,6 +38,7 @@ LJ_ASMF void lj_vm_callhook(void);
 /* Trace exit handling. */
 LJ_ASMF void lj_vm_exit_handler(void);
 LJ_ASMF void lj_vm_exit_interp(void);
+LJ_ASMF void lj_vm_exit_interp_notrack(void);
 
 /* Internal math helper functions. */
 LJ_ASMF double lj_vm_floor(double);

src/lj_vmprofile.c

@@ -88,20 +88,20 @@ static void start_timer(int interval)
  struct sigaction sa;
  tm.it_value.tv_sec = tm.it_interval.tv_sec = interval / 1000;
  tm.it_value.tv_usec = tm.it_interval.tv_usec = (interval % 1000) * 1000;
- setitimer(ITIMER_PROF, &tm, NULL);
+ setitimer(ITIMER_VIRTUAL, &tm, NULL);
  sa.sa_flags = SA_SIGINFO | SA_RESTART;
  sa.sa_sigaction = vmprofile_signal;
  sigemptyset(&sa.sa_mask);
- sigaction(SIGPROF, &sa, &state.oldsa);
+ sigaction(SIGVTALRM, &sa, &state.oldsa);
 }
 
 static void stop_timer()
 {
  struct itimerval tm;
  tm.it_value.tv_sec = tm.it_interval.tv_sec = 0;
  tm.it_value.tv_usec = tm.it_interval.tv_usec = 0;
- setitimer(ITIMER_PROF, &tm, NULL);
- sigaction(SIGPROF, NULL, &state.oldsa);
+ setitimer(ITIMER_VIRTUAL, &tm, NULL);
+ sigaction(SIGVTALRM, NULL, &state.oldsa);
 }
 
 /* -- State that the application can manage via FFI ----------------------- */