From fb79f500af1b4d9ee5685e8934726b5e2ea4edd5 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 22 Jun 2011 22:39:25 +0200
Subject: [PATCH] re PR libgomp/49490 (suboptimal load balancing in loops)
PR libgomp/49490
* omp-low.c (expand_omp_for_static_nochunk): Only
use n ceil/ nthreads size for the first
n % nthreads threads in the team instead of
all threads except for the last few ones which
get less work or none at all.
* iter.c (gomp_iter_static_next): For chunk size 0
only use n ceil/ nthreads size for the first
n % nthreads threads in the team instead of
all threads except for the last few ones which
get less work or none at all.
* iter_ull.c (gomp_iter_ull_static_next): Likewise.
* env.c (parse_schedule): If OMP_SCHEDULE doesn't have
chunk argument, set run_sched_modifier to 0 for static
resp. 1 for other kinds. If chunk argument is 0
and not static, set value to 1.
From-SVN: r175315
---
gcc/ChangeLog | 7 +++++
gcc/omp-low.c | 64 +++++++++++++++++++++++++++++++++++-----------
libgomp/ChangeLog | 14 ++++++++++
libgomp/env.c | 10 ++++++--
libgomp/iter.c | 15 ++++++-----
libgomp/iter_ull.c | 15 ++++++-----
6 files changed, 96 insertions(+), 29 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5b5964db18a3..d4ee63b825df 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,12 @@
2011-06-22 Jakub Jelinek <jakub@redhat.com>
+ PR libgomp/49490
+ * omp-low.c (expand_omp_for_static_nochunk): Only
+ use n ceil/ nthreads size for the first
+ n % nthreads threads in the team instead of
+ all threads except for the last few ones which
+ get less work or none at all.
+
PR debug/49496
* tree-vect-patterns.c (vect_recog_widen_mult_pattern): Ignore debug
uses.
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 944a40bce979..05646bf8833c 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -3,7 +3,7 @@
marshalling to implement data sharing and copying clauses.
Contributed by Diego Novillo <dnovillo@redhat.com>
- Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+ Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
This file is part of GCC.
@@ -4108,9 +4108,14 @@ expand_omp_for_generic (struct omp_region *region,
else
n = (adj + N2 - N1) / STEP;
q = n / nthreads;
- q += (q * nthreads != n);
- s0 = q * threadid;
- e0 = min(s0 + q, n);
+ tt = n % nthreads;
+ if (threadid < tt) goto L3; else goto L4;
+ L3:
+ tt = 0;
+ q = q + 1;
+ L4:
+ s0 = q * threadid + tt;
+ e0 = s0 + q;
V = s0 * STEP + N1;
if (s0 >= e0) goto L2; else goto L0;
L0:
@@ -4126,12 +4131,14 @@ static void
expand_omp_for_static_nochunk (struct omp_region *region,
struct omp_for_data *fd)
{
- tree n, q, s0, e0, e, t, nthreads, threadid;
+ tree n, q, s0, e0, e, t, tt, nthreads, threadid;
tree type, itype, vmain, vback;
- basic_block entry_bb, exit_bb, seq_start_bb, body_bb, cont_bb;
+ basic_block entry_bb, second_bb, third_bb, exit_bb, seq_start_bb;
+ basic_block body_bb, cont_bb;
basic_block fin_bb;
gimple_stmt_iterator gsi;
gimple stmt;
+ edge ep;
itype = type = TREE_TYPE (fd->loop.v);
if (POINTER_TYPE_P (type))
@@ -4185,19 +4192,39 @@ expand_omp_for_static_nochunk (struct omp_region *region,
t = fold_convert (itype, t);
n = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
+ q = create_tmp_var (itype, "q");
t = fold_build2 (TRUNC_DIV_EXPR, itype, n, nthreads);
- q = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
+ t = force_gimple_operand_gsi (&gsi, t, false, NULL_TREE, true, GSI_SAME_STMT);
+ gsi_insert_before (&gsi, gimple_build_assign (q, t), GSI_SAME_STMT);
+
+ tt = create_tmp_var (itype, "tt");
+ t = fold_build2 (TRUNC_MOD_EXPR, itype, n, nthreads);
+ t = force_gimple_operand_gsi (&gsi, t, false, NULL_TREE, true, GSI_SAME_STMT);
+ gsi_insert_before (&gsi, gimple_build_assign (tt, t), GSI_SAME_STMT);
- t = fold_build2 (MULT_EXPR, itype, q, nthreads);
- t = fold_build2 (NE_EXPR, itype, t, n);
- t = fold_build2 (PLUS_EXPR, itype, q, t);
- q = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
+ t = build2 (LT_EXPR, boolean_type_node, threadid, tt);
+ stmt = gimple_build_cond_empty (t);
+ gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+
+ second_bb = split_block (entry_bb, stmt)->dest;
+ gsi = gsi_last_bb (second_bb);
+ gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_FOR);
+
+ gsi_insert_before (&gsi, gimple_build_assign (tt, build_int_cst (itype, 0)),
+ GSI_SAME_STMT);
+ stmt = gimple_build_assign_with_ops (PLUS_EXPR, q, q,
+ build_int_cst (itype, 1));
+ gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+
+ third_bb = split_block (second_bb, stmt)->dest;
+ gsi = gsi_last_bb (third_bb);
+ gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_FOR);
t = build2 (MULT_EXPR, itype, q, threadid);
+ t = build2 (PLUS_EXPR, itype, t, tt);
s0 = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
t = fold_build2 (PLUS_EXPR, itype, s0, q);
- t = fold_build2 (MIN_EXPR, itype, t, n);
e0 = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
t = build2 (GE_EXPR, boolean_type_node, s0, e0);
@@ -4263,13 +4290,20 @@ expand_omp_for_static_nochunk (struct omp_region *region,
gsi_remove (&gsi, true);
/* Connect all the blocks. */
- find_edge (entry_bb, seq_start_bb)->flags = EDGE_FALSE_VALUE;
- find_edge (entry_bb, fin_bb)->flags = EDGE_TRUE_VALUE;
+ ep = make_edge (entry_bb, third_bb, EDGE_FALSE_VALUE);
+ ep->probability = REG_BR_PROB_BASE / 4 * 3;
+ ep = find_edge (entry_bb, second_bb);
+ ep->flags = EDGE_TRUE_VALUE;
+ ep->probability = REG_BR_PROB_BASE / 4;
+ find_edge (third_bb, seq_start_bb)->flags = EDGE_FALSE_VALUE;
+ find_edge (third_bb, fin_bb)->flags = EDGE_TRUE_VALUE;
find_edge (cont_bb, body_bb)->flags = EDGE_TRUE_VALUE;
find_edge (cont_bb, fin_bb)->flags = EDGE_FALSE_VALUE;
- set_immediate_dominator (CDI_DOMINATORS, seq_start_bb, entry_bb);
+ set_immediate_dominator (CDI_DOMINATORS, second_bb, entry_bb);
+ set_immediate_dominator (CDI_DOMINATORS, third_bb, entry_bb);
+ set_immediate_dominator (CDI_DOMINATORS, seq_start_bb, third_bb);
set_immediate_dominator (CDI_DOMINATORS, body_bb,
recompute_dominator (CDI_DOMINATORS, body_bb));
set_immediate_dominator (CDI_DOMINATORS, fin_bb,
diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index 7d3fe227c5ea..1d93273b9190 100644
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,17 @@
+2011-06-22 Jakub Jelinek <jakub@redhat.com>
+
+ PR libgomp/49490
+ * iter.c (gomp_iter_static_next): For chunk size 0
+ only use n ceil/ nthreads size for the first
+ n % nthreads threads in the team instead of
+ all threads except for the last few ones which
+ get less work or none at all.
+ * iter_ull.c (gomp_iter_ull_static_next): Likewise.
+ * env.c (parse_schedule): If OMP_SCHEDULE doesn't have
+ chunk argument, set run_sched_modifier to 0 for static
+ resp. 1 for other kinds. If chunk argument is 0
+ and not static, set value to 1.
+
2011-05-19 Jakub Jelinek <jakub@redhat.com>
PR c++/49043
diff --git a/libgomp/env.c b/libgomp/env.c
index 92fa8c374979..0ca9a1c9e006 100644
--- a/libgomp/env.c
+++ b/libgomp/env.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+/* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
@@ -108,7 +108,11 @@ parse_schedule (void)
while (isspace ((unsigned char) *env))
++env;
if (*env == '\0')
- return;
+ {
+ gomp_global_icv.run_sched_modifier
+ = gomp_global_icv.run_sched_var != GFS_STATIC;
+ return;
+ }
if (*env++ != ',')
goto unknown;
while (isspace ((unsigned char) *env))
@@ -129,6 +133,8 @@ parse_schedule (void)
if ((int)value != value)
goto invalid;
+ if (value == 0 && gomp_global_icv.run_sched_var != GFS_STATIC)
+ value = 1;
gomp_global_icv.run_sched_modifier = value;
return;
diff --git a/libgomp/iter.c b/libgomp/iter.c
index 9ec4dbd2252e..cd9484a1ea4c 100644
--- a/libgomp/iter.c
+++ b/libgomp/iter.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2005, 2008, 2009, 2011 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU OpenMP Library (libgomp).
@@ -59,7 +59,7 @@ gomp_iter_static_next (long *pstart, long *pend)
trip through the outer loop. */
if (ws->chunk_size == 0)
{
- unsigned long n, q, i;
+ unsigned long n, q, i, t;
unsigned long s0, e0;
long s, e;
@@ -74,11 +74,14 @@ gomp_iter_static_next (long *pstart, long *pend)
/* Compute the "zero-based" start and end points. That is, as
if the loop began at zero and incremented by one. */
q = n / nthreads;
- q += (q * nthreads != n);
- s0 = q * i;
+ t = n % nthreads;
+ if (i < t)
+ {
+ t = 0;
+ q++;
+ }
+ s0 = q * i + t;
e0 = s0 + q;
- if (e0 > n)
- e0 = n;
/* Notice when no iterations allocated for this thread. */
if (s0 >= e0)
diff --git a/libgomp/iter_ull.c b/libgomp/iter_ull.c
index 1754e6333c2d..a393920b55e4 100644
--- a/libgomp/iter_ull.c
+++ b/libgomp/iter_ull.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2005, 2008, 2009, 2011 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU OpenMP Library (libgomp).
@@ -60,7 +60,7 @@ gomp_iter_ull_static_next (gomp_ull *pstart, gomp_ull *pend)
trip through the outer loop. */
if (ws->chunk_size_ull == 0)
{
- gomp_ull n, q, i, s0, e0, s, e;
+ gomp_ull n, q, i, t, s0, e0, s, e;
if (thr->ts.static_trip > 0)
return 1;
@@ -75,11 +75,14 @@ gomp_iter_ull_static_next (gomp_ull *pstart, gomp_ull *pend)
/* Compute the "zero-based" start and end points. That is, as
if the loop began at zero and incremented by one. */
q = n / nthreads;
- q += (q * nthreads != n);
- s0 = q * i;
+ t = n % nthreads;
+ if (i < t)
+ {
+ t = 0;
+ q++;
+ }
+ s0 = q * i + t;
e0 = s0 + q;
- if (e0 > n)
- e0 = n;
/* Notice when no iterations allocated for this thread. */
if (s0 >= e0)
--
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