From: Robin Dapp <rdapp@linux.vnet.ibm.com>
Date: Wed, 18 Oct 2017 09:10:09 +0000 (+0000)
Subject: S/390: Handle long-running instructions.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=67ba339309e7949cba2f27d3237156440d73d604;p=gcc.git

S/390: Handle long-running instructions.

gcc/ChangeLog:

2017-10-18  Robin Dapp  <rdapp@linux.vnet.ibm.com>

	* config/s390/s390.c (NUM_SIDES): New variable.
	(LONGRUNNING_THRESHOLD): New variable.
	(LATENCY_FACTOR): New variable.
	(s390_sched_score): Decrease score for long-running instructions on
	wrong side.
	(s390_sched_variable_issue): Perform bookkeeping for long-running
	instructions.

From-SVN: r253849
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5d0dd0b2cef..5850f0035dc 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2017-10-18  Robin Dapp  <rdapp@linux.vnet.ibm.com>
+
+	* config/s390/s390.c (NUM_SIDES): New variable.
+	(LONGRUNNING_THRESHOLD): New variable.
+	(LATENCY_FACTOR): New variable.
+	(s390_sched_score): Decrease score for long-running instructions on
+	wrong side.
+	(s390_sched_variable_issue): Perform bookkeeping for long-running
+	instructions.
+
 2017-10-18  Richard Biener  <rguenther@suse.de>
 
 	* graphite-isl-ast-to-gimple.c (gcc_expression_from_isl_ast_expr_id):
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 6e3ac3b7d0f..021993f7942 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -355,6 +355,18 @@ static rtx_insn *last_scheduled_insn;
 #define MAX_SCHED_UNITS 3
 static int last_scheduled_unit_distance[MAX_SCHED_UNITS];
 
+#define NUM_SIDES 2
+static int current_side = 1;
+#define LONGRUNNING_THRESHOLD 5
+
+/* Estimate of number of cycles a long-running insn occupies an
+   execution unit.  */
+static unsigned fxu_longrunning[NUM_SIDES];
+static unsigned vfu_longrunning[NUM_SIDES];
+
+/* Factor to scale latencies by, determined by measurements.  */
+#define LATENCY_FACTOR 4
+
 /* The maximum score added for an instruction whose unit hasn't been
    in use for MAX_SCHED_MIX_DISTANCE steps.  Increase this value to
    give instruction mix scheduling more priority over instruction
@@ -14755,7 +14767,24 @@ s390_sched_score (rtx_insn *insn)
 	if (m & unit_mask)
 	  score += (last_scheduled_unit_distance[i] * MAX_SCHED_MIX_SCORE /
 		    MAX_SCHED_MIX_DISTANCE);
+
+      unsigned latency = insn_default_latency (insn);
+
+      int other_side = 1 - current_side;
+
+      /* Try to delay long-running insns when side is busy.  */
+      if (latency > LONGRUNNING_THRESHOLD)
+	{
+	  if (get_attr_z13_unit_fxu (insn) && fxu_longrunning[current_side]
+	      && fxu_longrunning[other_side] <= fxu_longrunning[current_side])
+	    score = MAX (0, score - 10);
+
+	  if (get_attr_z13_unit_vfu (insn) && vfu_longrunning[current_side]
+	      && vfu_longrunning[other_side] <= vfu_longrunning[current_side])
+	    score = MAX (0, score - 10);
+	}
     }
+
   return score;
 }
 
@@ -14874,12 +14903,19 @@ s390_sched_variable_issue (FILE *file, int verbose, rtx_insn *insn, int more)
 {
   last_scheduled_insn = insn;
 
+  bool starts_group = false;
+
   if (s390_tune >= PROCESSOR_2827_ZEC12
       && reload_completed
       && recog_memoized (insn) >= 0)
     {
       unsigned int mask = s390_get_sched_attrmask (insn);
 
+      if ((mask & S390_SCHED_ATTR_MASK_CRACKED) != 0
+	  || (mask & S390_SCHED_ATTR_MASK_EXPANDED) != 0
+	  || (mask & S390_SCHED_ATTR_MASK_GROUPALONE) != 0)
+	starts_group = true;
+
       if ((mask & S390_SCHED_ATTR_MASK_CRACKED) != 0
 	  || (mask & S390_SCHED_ATTR_MASK_EXPANDED) != 0)
 	s390_sched_state = S390_SCHED_STATE_CRACKED;
@@ -14892,14 +14928,15 @@ s390_sched_variable_issue (FILE *file, int verbose, rtx_insn *insn, int more)
 	  switch (s390_sched_state)
 	    {
 	    case 0:
+	      starts_group = true;
+	      /* fallthrough */
 	    case 1:
 	    case 2:
+	      s390_sched_state++;
+	      break;
 	    case S390_SCHED_STATE_NORMAL:
-	      if (s390_sched_state == S390_SCHED_STATE_NORMAL)
-		s390_sched_state = 1;
-	      else
-		s390_sched_state++;
-
+	      starts_group = true;
+	      s390_sched_state = 1;
 	      break;
 	    case S390_SCHED_STATE_CRACKED:
 	      s390_sched_state = S390_SCHED_STATE_NORMAL;
@@ -14922,6 +14959,27 @@ s390_sched_variable_issue (FILE *file, int verbose, rtx_insn *insn, int more)
 	      last_scheduled_unit_distance[i]++;
 	}
 
+      /* If this insn started a new group, the side flipped.  */
+      if (starts_group)
+	current_side = current_side ? 0 : 1;
+
+      for (int i = 0; i < 2; i++)
+	{
+	  if (fxu_longrunning[i] >= 1)
+	    fxu_longrunning[i] -= 1;
+	  if (vfu_longrunning[i] >= 1)
+	    vfu_longrunning[i] -= 1;
+	}
+
+      unsigned latency = insn_default_latency (insn);
+      if (latency > LONGRUNNING_THRESHOLD)
+	{
+	  if (get_attr_z13_unit_fxu (insn))
+	    fxu_longrunning[current_side] = latency * LATENCY_FACTOR;
+	  else
+	    vfu_longrunning[current_side] = latency * LATENCY_FACTOR;
+	}
+
       if (verbose > 5)
 	{
 	  unsigned int sched_mask;