From 139175f8c48af3ceefb6838dabc0f1222fd150b1 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Tue, 3 May 2011 21:14:18 +0200
Subject: [PATCH] Tune loop unrolling heuristics. Increase trace recorder
 limits.

---
 doc/running.html | 6 +++---
 src/lj_jit.h     | 6 +++---
 src/lj_record.c  | 4 +++-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/doc/running.html b/doc/running.html
index cf221a4d..76a393ba 100644
--- a/doc/running.html
+++ b/doc/running.html
@@ -213,13 +213,13 @@ Here are the parameters and their default settings:
 <tr class="odd separate">
 <td class="param_name">maxtrace</td><td class="param_default">1000</td><td class="param_desc">Max. number of traces in the cache</td></tr>
 <tr class="even">
-<td class="param_name">maxrecord</td><td class="param_default">2000</td><td class="param_desc">Max. number of recorded IR instructions</td></tr>
+<td class="param_name">maxrecord</td><td class="param_default">4000</td><td class="param_desc">Max. number of recorded IR instructions</td></tr>
 <tr class="odd">
 <td class="param_name">maxirconst</td><td class="param_default">500</td><td class="param_desc">Max. number of IR constants of a trace</td></tr>
 <tr class="even">
 <td class="param_name">maxside</td><td class="param_default">100</td><td class="param_desc">Max. number of side traces of a root trace</td></tr>
 <tr class="odd">
-<td class="param_name">maxsnap</td><td class="param_default">100</td><td class="param_desc">Max. number of snapshots for a trace</td></tr>
+<td class="param_name">maxsnap</td><td class="param_default">500</td><td class="param_desc">Max. number of snapshots for a trace</td></tr>
 <tr class="even separate">
 <td class="param_name">hotloop</td><td class="param_default">56</td><td class="param_desc">Number of iterations to detect a hot loop or hot call</td></tr>
 <tr class="odd">
@@ -229,7 +229,7 @@ Here are the parameters and their default settings:
 <tr class="odd separate">
 <td class="param_name">instunroll</td><td class="param_default">4</td><td class="param_desc">Max. unroll factor for instable loops</td></tr>
 <tr class="even">
-<td class="param_name">loopunroll</td><td class="param_default">7</td><td class="param_desc">Max. unroll factor for loop ops in side traces</td></tr>
+<td class="param_name">loopunroll</td><td class="param_default">15</td><td class="param_desc">Max. unroll factor for loop ops in side traces</td></tr>
 <tr class="odd">
 <td class="param_name">callunroll</td><td class="param_default">3</td><td class="param_desc">Max. unroll factor for pseudo-recursive calls</td></tr>
 <tr class="even">
diff --git a/src/lj_jit.h b/src/lj_jit.h
index 92631440..cced4813 100644
--- a/src/lj_jit.h
+++ b/src/lj_jit.h
@@ -67,17 +67,17 @@
 /* Optimization parameters and their defaults. Length is a char in octal! */
 #define JIT_PARAMDEF(_) \
   _(\010, maxtrace,	1000)	/* Max. # of traces in cache. */ \
-  _(\011, maxrecord,	2000)	/* Max. # of recorded IR instructions. */ \
+  _(\011, maxrecord,	4000)	/* Max. # of recorded IR instructions. */ \
   _(\012, maxirconst,	500)	/* Max. # of IR constants of a trace. */ \
   _(\007, maxside,	100)	/* Max. # of side traces of a root trace. */ \
-  _(\007, maxsnap,	100)	/* Max. # of snapshots for a trace. */ \
+  _(\007, maxsnap,	500)	/* Max. # of snapshots for a trace. */ \
   \
   _(\007, hotloop,	56)	/* # of iter. to detect a hot loop/call. */ \
   _(\007, hotexit,	10)	/* # of taken exits to start a side trace. */ \
   _(\007, tryside,	4)	/* # of attempts to compile a side trace. */ \
   \
   _(\012, instunroll,	4)	/* Max. unroll for instable loops. */ \
-  _(\012, loopunroll,	7)	/* Max. unroll for loop ops in side traces. */ \
+  _(\012, loopunroll,	15)	/* Max. unroll for loop ops in side traces. */ \
   _(\012, callunroll,	3)	/* Max. unroll for recursive calls. */ \
   _(\011, recunroll,	2)	/* Min. unroll for true recursion. */ \
   \
diff --git a/src/lj_record.c b/src/lj_record.c
index 36425086..41b2221a 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -521,7 +521,9 @@ static void rec_loop_interp(jit_State *J, const BCIns *pc, LoopEvent ev)
       */
       if (!innerloopleft(J, pc))
 	lj_trace_err(J, LJ_TRERR_LINNER);  /* Root trace hit an inner loop. */
-      if ((J->loopref && J->cur.nins - J->loopref > 8) || --J->loopunroll < 0)
+      if ((J->loopref && J->cur.nins - J->loopref >
+			 ((IRRef)J->param[JIT_P_maxrecord] >> 5)) ||
+	  --J->loopunroll < 0)
 	lj_trace_err(J, LJ_TRERR_LUNROLL);  /* Limit loop unrolling. */
       J->loopref = J->cur.nins;
     }