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author | Jakub Jelinek <jakub@redhat.com> | 2011-06-22 22:39:25 +0200 |
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committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2011-06-22 22:39:25 +0200 |
commit | fb79f500af1b4d9ee5685e8934726b5e2ea4edd5 (patch) | |
tree | c2cc34ab7a462c76b41fcd457b365ba285e84685 /libgomp/iter_ull.c | |
parent | 4fb489e7968448aaa9321d863660530a81d06f4c (diff) | |
download | gcc-fb79f500af1b4d9ee5685e8934726b5e2ea4edd5.zip gcc-fb79f500af1b4d9ee5685e8934726b5e2ea4edd5.tar.gz gcc-fb79f500af1b4d9ee5685e8934726b5e2ea4edd5.tar.bz2 |
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
Diffstat (limited to 'libgomp/iter_ull.c')
-rw-r--r-- | libgomp/iter_ull.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/libgomp/iter_ull.c b/libgomp/iter_ull.c index 1754e63..a393920 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) |