X-Git-Url: https://oss.titaniummirror.com/gitweb?a=blobdiff_plain;f=libgomp%2Fiter_ull.c;fp=libgomp%2Fiter_ull.c;h=1754e6333c2d5f4b0266bfeba840b119eba3481c;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=0000000000000000000000000000000000000000;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/libgomp/iter_ull.c b/libgomp/iter_ull.c new file mode 100644 index 00000000..1754e633 --- /dev/null +++ b/libgomp/iter_ull.c @@ -0,0 +1,341 @@ +/* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc. + Contributed by Richard Henderson . + + This file is part of the GNU OpenMP Library (libgomp). + + Libgomp is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + FOR A PARTICULAR PURPOSE. See the GNU General Public License for + more details. + + Under Section 7 of GPL version 3, you are granted additional + permissions described in the GCC Runtime Library Exception, version + 3.1, as published by the Free Software Foundation. + + You should have received a copy of the GNU General Public License and + a copy of the GCC Runtime Library Exception along with this program; + see the files COPYING3 and COPYING.RUNTIME respectively. If not, see + . */ + +/* This file contains routines for managing work-share iteration, both + for loops and sections. */ + +#include "libgomp.h" +#include + +typedef unsigned long long gomp_ull; + +/* This function implements the STATIC scheduling method. The caller should + iterate *pstart <= x < *pend. Return zero if there are more iterations + to perform; nonzero if not. Return less than 0 if this thread had + received the absolutely last iteration. */ + +int +gomp_iter_ull_static_next (gomp_ull *pstart, gomp_ull *pend) +{ + struct gomp_thread *thr = gomp_thread (); + struct gomp_team *team = thr->ts.team; + struct gomp_work_share *ws = thr->ts.work_share; + unsigned long nthreads = team ? team->nthreads : 1; + + if (thr->ts.static_trip == -1) + return -1; + + /* Quick test for degenerate teams and orphaned constructs. */ + if (nthreads == 1) + { + *pstart = ws->next_ull; + *pend = ws->end_ull; + thr->ts.static_trip = -1; + return ws->next_ull == ws->end_ull; + } + + /* We interpret chunk_size zero as "unspecified", which means that we + should break up the iterations such that each thread makes only one + trip through the outer loop. */ + if (ws->chunk_size_ull == 0) + { + gomp_ull n, q, i, s0, e0, s, e; + + if (thr->ts.static_trip > 0) + return 1; + + /* Compute the total number of iterations. */ + if (__builtin_expect (ws->mode, 0) == 0) + n = (ws->end_ull - ws->next_ull + ws->incr_ull - 1) / ws->incr_ull; + else + n = (ws->next_ull - ws->end_ull - ws->incr_ull - 1) / -ws->incr_ull; + i = thr->ts.team_id; + + /* 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; + e0 = s0 + q; + if (e0 > n) + e0 = n; + + /* Notice when no iterations allocated for this thread. */ + if (s0 >= e0) + { + thr->ts.static_trip = 1; + return 1; + } + + /* Transform these to the actual start and end numbers. */ + s = s0 * ws->incr_ull + ws->next_ull; + e = e0 * ws->incr_ull + ws->next_ull; + + *pstart = s; + *pend = e; + thr->ts.static_trip = (e0 == n ? -1 : 1); + return 0; + } + else + { + gomp_ull n, s0, e0, i, c, s, e; + + /* Otherwise, each thread gets exactly chunk_size iterations + (if available) each time through the loop. */ + + if (__builtin_expect (ws->mode, 0) == 0) + n = (ws->end_ull - ws->next_ull + ws->incr_ull - 1) / ws->incr_ull; + else + n = (ws->next_ull - ws->end_ull - ws->incr_ull - 1) / -ws->incr_ull; + i = thr->ts.team_id; + c = ws->chunk_size_ull; + + /* Initial guess is a C sized chunk positioned nthreads iterations + in, offset by our thread number. */ + s0 = (thr->ts.static_trip * (gomp_ull) nthreads + i) * c; + e0 = s0 + c; + + /* Detect overflow. */ + if (s0 >= n) + return 1; + if (e0 > n) + e0 = n; + + /* Transform these to the actual start and end numbers. */ + s = s0 * ws->incr_ull + ws->next_ull; + e = e0 * ws->incr_ull + ws->next_ull; + + *pstart = s; + *pend = e; + + if (e0 == n) + thr->ts.static_trip = -1; + else + thr->ts.static_trip++; + return 0; + } +} + + +/* This function implements the DYNAMIC scheduling method. Arguments are + as for gomp_iter_ull_static_next. This function must be called with + ws->lock held. */ + +bool +gomp_iter_ull_dynamic_next_locked (gomp_ull *pstart, gomp_ull *pend) +{ + struct gomp_thread *thr = gomp_thread (); + struct gomp_work_share *ws = thr->ts.work_share; + gomp_ull start, end, chunk, left; + + start = ws->next_ull; + if (start == ws->end_ull) + return false; + + chunk = ws->chunk_size_ull; + left = ws->end_ull - start; + if (__builtin_expect (ws->mode & 2, 0)) + { + if (chunk < left) + chunk = left; + } + else + { + if (chunk > left) + chunk = left; + } + end = start + chunk; + + ws->next_ull = end; + *pstart = start; + *pend = end; + return true; +} + + +#if defined HAVE_SYNC_BUILTINS && defined __LP64__ +/* Similar, but doesn't require the lock held, and uses compare-and-swap + instead. Note that the only memory value that changes is ws->next_ull. */ + +bool +gomp_iter_ull_dynamic_next (gomp_ull *pstart, gomp_ull *pend) +{ + struct gomp_thread *thr = gomp_thread (); + struct gomp_work_share *ws = thr->ts.work_share; + gomp_ull start, end, nend, chunk; + + end = ws->end_ull; + chunk = ws->chunk_size_ull; + + if (__builtin_expect (ws->mode & 1, 1)) + { + gomp_ull tmp = __sync_fetch_and_add (&ws->next_ull, chunk); + if (__builtin_expect (ws->mode & 2, 0) == 0) + { + if (tmp >= end) + return false; + nend = tmp + chunk; + if (nend > end) + nend = end; + *pstart = tmp; + *pend = nend; + return true; + } + else + { + if (tmp <= end) + return false; + nend = tmp + chunk; + if (nend < end) + nend = end; + *pstart = tmp; + *pend = nend; + return true; + } + } + + start = ws->next_ull; + while (1) + { + gomp_ull left = end - start; + gomp_ull tmp; + + if (start == end) + return false; + + if (__builtin_expect (ws->mode & 2, 0)) + { + if (chunk < left) + chunk = left; + } + else + { + if (chunk > left) + chunk = left; + } + nend = start + chunk; + + tmp = __sync_val_compare_and_swap (&ws->next_ull, start, nend); + if (__builtin_expect (tmp == start, 1)) + break; + + start = tmp; + } + + *pstart = start; + *pend = nend; + return true; +} +#endif /* HAVE_SYNC_BUILTINS */ + + +/* This function implements the GUIDED scheduling method. Arguments are + as for gomp_iter_ull_static_next. This function must be called with the + work share lock held. */ + +bool +gomp_iter_ull_guided_next_locked (gomp_ull *pstart, gomp_ull *pend) +{ + struct gomp_thread *thr = gomp_thread (); + struct gomp_work_share *ws = thr->ts.work_share; + struct gomp_team *team = thr->ts.team; + gomp_ull nthreads = team ? team->nthreads : 1; + gomp_ull n, q; + gomp_ull start, end; + + if (ws->next_ull == ws->end_ull) + return false; + + start = ws->next_ull; + if (__builtin_expect (ws->mode, 0) == 0) + n = (ws->end_ull - start) / ws->incr_ull; + else + n = (start - ws->end_ull) / -ws->incr_ull; + q = (n + nthreads - 1) / nthreads; + + if (q < ws->chunk_size_ull) + q = ws->chunk_size_ull; + if (q <= n) + end = start + q * ws->incr_ull; + else + end = ws->end_ull; + + ws->next_ull = end; + *pstart = start; + *pend = end; + return true; +} + +#if defined HAVE_SYNC_BUILTINS && defined __LP64__ +/* Similar, but doesn't require the lock held, and uses compare-and-swap + instead. Note that the only memory value that changes is ws->next_ull. */ + +bool +gomp_iter_ull_guided_next (gomp_ull *pstart, gomp_ull *pend) +{ + struct gomp_thread *thr = gomp_thread (); + struct gomp_work_share *ws = thr->ts.work_share; + struct gomp_team *team = thr->ts.team; + gomp_ull nthreads = team ? team->nthreads : 1; + gomp_ull start, end, nend, incr; + gomp_ull chunk_size; + + start = ws->next_ull; + end = ws->end_ull; + incr = ws->incr_ull; + chunk_size = ws->chunk_size_ull; + + while (1) + { + gomp_ull n, q; + gomp_ull tmp; + + if (start == end) + return false; + + if (__builtin_expect (ws->mode, 0) == 0) + n = (end - start) / incr; + else + n = (start - end) / -incr; + q = (n + nthreads - 1) / nthreads; + + if (q < chunk_size) + q = chunk_size; + if (__builtin_expect (q <= n, 1)) + nend = start + q * incr; + else + nend = end; + + tmp = __sync_val_compare_and_swap (&ws->next_ull, start, nend); + if (__builtin_expect (tmp == start, 1)) + break; + + start = tmp; + } + + *pstart = start; + *pend = nend; + return true; +} +#endif /* HAVE_SYNC_BUILTINS */