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* [PATCH] Change PRED_LOOP_EXIT from 85 to 92
@ 2017-12-22 22:49 David Esparza
  2017-12-23 22:08 ` Segher Boessenkool
  0 siblings, 1 reply; 8+ messages in thread
From: David Esparza @ 2017-12-22 22:49 UTC (permalink / raw)
  To: gcc-patches; +Cc: David Esparza

With a value of 85 GCC has a CPU performance degradation of 11%,
reverting PRED_LOOP_EXIT to 92 this degradation disappear.
Those values where measured by running c-ray ray-tracer that is a
floating point benchmark that runs out of L1 cache.

Signed-off-by: David Esparza <david.esparza.borquez@intel.com>
---
 contrib/analyze_brprob.py        | 4 ++--
 gcc/ChangeLog                    | 4 ----
 gcc/predict.def                  | 2 +-
 gcc/testsuite/gcc.dg/predict-9.c | 4 ++--
 4 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/contrib/analyze_brprob.py b/contrib/analyze_brprob.py
index 2526623ff55..9808c46de16 100755
--- a/contrib/analyze_brprob.py
+++ b/contrib/analyze_brprob.py
@@ -119,10 +119,10 @@ class Profile:
         elif sorting == 'coverage':
             sorter = lambda x: x[1].count
 
-        print('%-40s %8s %6s  %-16s %14s %8s %6s' % ('HEURISTICS', 'BRANCHES', '(REL)',
+        print('%-36s %8s %6s  %-16s %14s %8s %6s' % ('HEURISTICS', 'BRANCHES', '(REL)',
               'HITRATE', 'COVERAGE', 'COVERAGE', '(REL)'))
         for (k, v) in sorted(self.heuristics.items(), key = sorter):
-            print('%-40s %8i %5.1f%% %6.2f%% / %6.2f%% %14i %8s %5.1f%%' %
+            print('%-36s %8i %5.1f%% %6.2f%% / %6.2f%% %14i %8s %5.1f%%' %
             (k, v.branches, percentage(v.branches, self.branches_max ()),
              percentage(v.hits, v.count), percentage(v.fits, v.count),
              v.count, v.count_formatted(), percentage(v.count, self.count_max()) ))
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a93464d33a7..0f4846c2c4d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,7 +1,3 @@
-2016-06-17  Martin Liska  <mliska@suse.cz>
-
-	* predict.def: PRED_LOOP_EXIT from 92 to 85.
-
 2016-06-17  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* config/arm/arm_neon.h (vadd_f32): replace __FAST_MATH with
diff --git a/gcc/predict.def b/gcc/predict.def
index d3bc757bb97..a0d0ba923a2 100644
--- a/gcc/predict.def
+++ b/gcc/predict.def
@@ -89,7 +89,7 @@ DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY,
 	       PRED_FLAG_FIRST_MATCH)
 
 /* Edge causing loop to terminate is probably not taken.  */
-DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (85),
+DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (92),
 	       PRED_FLAG_FIRST_MATCH)
 
 /* Edge causing loop to terminate by computing value used by later
diff --git a/gcc/testsuite/gcc.dg/predict-9.c b/gcc/testsuite/gcc.dg/predict-9.c
index 196e31c60ee..a613961091d 100644
--- a/gcc/testsuite/gcc.dg/predict-9.c
+++ b/gcc/testsuite/gcc.dg/predict-9.c
@@ -19,5 +19,5 @@ void foo (int base)
   }
 }
 
-/* { dg-final { scan-tree-dump-times "first match heuristics: 3.0%" 3 "profile_estimate"} } */
-/* { dg-final { scan-tree-dump-times "first match heuristics: 7.5%" 1 "profile_estimate"} } */
+/* { dg-final { scan-tree-dump-times "first match heuristics: 2.0%" 3 "profile_estimate"} } */
+/* { dg-final { scan-tree-dump-times "first match heuristics: 4.0%" 1 "profile_estimate"} } */
-- 
2.15.1

^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-01-22  8:16 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-12-22 22:49 [PATCH] Change PRED_LOOP_EXIT from 85 to 92 David Esparza
2017-12-23 22:08 ` Segher Boessenkool
2017-12-24  9:13   ` Richard Sandiford
2017-12-24 12:03     ` Segher Boessenkool
2017-12-24 18:58       ` Jeff Law
2018-01-02 11:57         ` Martin Liška
2018-01-02 16:37           ` Jeff Law
2018-01-22  8:57           ` Martin Liška

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