From: Ian Jackson Date: Sat, 8 Mar 2014 22:11:59 +0000 (+0000) Subject: Merge remote-tracking branch 'sgt/master' X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=8e7519302ad8da8ecb172cd863e8835abfa7b9e1;hp=--cc;p=matchsticks-search.git Merge remote-tracking branch 'sgt/master' Changes made to the new code in sgt/master: - use "-std=gnu99" not "--std=gnu99" - n_over_best calculation is in set_best - n_over_best initialised properly style: - use calloc, do not cast return value from int, better sizeof - extra blank line Conflicts: Makefile main.c --- 8e7519302ad8da8ecb172cd863e8835abfa7b9e1 diff --cc main.c index fd0569b,3c1b123..2fc3a51 --- a/main.c +++ b/main.c @@@ -94,240 -86,11 +94,244 @@@ static double best static glp_prob *best_prob; static AdjWord *best_adjmatrix; + static int n_over_best; + static int *weight; + static unsigned printcounter; +static void iterate(void); +static void iterate_recurse(int i, AdjWord min); +static bool preconsider_ok(int nwords, bool doprint); +static bool maxhamweight_ok(void); +static void optimise(bool doprint); + +static void progress_eol(void) { + fprintf(stderr," \r"); + fflush(stderr); +} + +static void set_best(double new_best) { + best = new_best; ++ n_over_best = n / best; +} + +/*----- multicore support -----*/ + +/* + * Multicore protocol + * + * We fork into: + * - master (parent) + * - generator + * - ncpu workers + * + * ipc facilities: + * - one pipe ("work") from generator to workers + * - ever-extending file ("bus") containing new "best" values + * - one file for each worker giving maxhamweight and adjmatrix for best + * + * generator runs iterate_recurse to a certain depth and writes the + * candidates to a pipe + * + * workers read candidates from the pipe and resume iterate_recurse + * halfway through the recursion + * + * whenever a worker does a doprint, it checks the bus for new best + * value; actual best values are appended + * + * master waits for generator and all workers to finish and then + * runs optimise() for each worker's best, then prints + */ + +static int ncpus = 0, multicore_iteration_boundary = INT_MAX; + +static int mc_bus, mc_work[2]; +static off_t mc_bus_read; + +typedef struct { + int w; + FILE *results; + pid_t pid; +} Worker; +static Worker *mc_us; + +static void multicore_check_for_new_best(void); + +#define MAX_NIOVS 3 +static AdjWord mc_iter_min; +static int mc_niovs; +static size_t mc_iovlen; +static struct iovec mc_iov[MAX_NIOVS]; + +#define IOV0 (mc_niovs = mc_iovlen = 0) + +#define IOV(obj, count) ({ \ + assert(mc_niovs < MAX_NIOVS); \ + mc_iov[mc_niovs].iov_base = &(obj); \ + mc_iov[mc_niovs].iov_len = sizeof(obj) * (count); \ + mc_iovlen += mc_iov[mc_niovs].iov_len; \ + mc_niovs++; \ + }) + +static void mc_rwvsetup_outer(void) { + IOV0; + IOV(maxhamweight, 1); + IOV(mc_iter_min, 1); + IOV(*adjmatrix, multicore_iteration_boundary); +} + +static void mc_rwvsetup_full(void) { + IOV0; + IOV(*adjmatrix, n); +} + +static void vlprintf(const char *fmt, va_list al) { + vfprintf(stderr,fmt,al); + progress_eol(); +} + +static void LPRINTF(const char *fmt, ...) { + va_list al; + va_start(al,fmt); + vlprintf(fmt,al); + va_end(al); +} + +static void mc_awaitpid(int wnum, pid_t pid) { + LPRINTF("master awaiting %2d [%ld]",wnum,(long)pid); + int status; + pid_t got = waitpid(pid, &status, 0); + assert(got == pid); + if (status) { + fprintf(stderr,"\nFAILED SUBPROC %2d [%ld] %d\n", + wnum, (long)pid, status); + exit(-1); + } +} + +static void multicore_outer_iteration(int i, AdjWord min) { + static unsigned check_counter; + + assert(i == multicore_iteration_boundary); + mc_iter_min = min; + mc_rwvsetup_outer(); + ssize_t r = writev(mc_work[1], mc_iov, mc_niovs); + assert(r == mc_iovlen); + /* effectively, this writev arranges to transfers control + * to some worker's instance of iterate_recurse via mc_iterate_worker */ + + if (!(check_counter++ & 0xff)) + multicore_check_for_new_best(); +} + +static void mc_iterate_worker(void) { + for (;;) { + mc_rwvsetup_outer(); + ssize_t r = readv(mc_work[0], mc_iov, mc_niovs); + if (r == 0) break; + assert(r == mc_iovlen); + + bool ok = maxhamweight_ok(); + if (!ok) continue; + + ok = preconsider_ok(multicore_iteration_boundary, 1); + progress_eol(); + if (!ok) continue; + + /* stop iterate_recurse from trying to run multicore_outer_iteration */ + int mc_org_it_bound = multicore_iteration_boundary; + multicore_iteration_boundary = INT_MAX; + iterate_recurse(mc_org_it_bound, mc_iter_min); + multicore_iteration_boundary = mc_org_it_bound; + } + LPRINTF("worker %2d reporting",mc_us->w); + if (best_adjmatrix) { + adjmatrix = best_adjmatrix; + mc_rwvsetup_full(); + ssize_t r = writev(fileno(mc_us->results), mc_iov, mc_niovs); + assert(r == mc_iovlen); + } + LPRINTF("worker %2d ending",mc_us->w); + exit(0); +} + +static void multicore(void) { + Worker *mc_workers; + int w; + pid_t genpid; + + multicore_iteration_boundary = n / 2; + + FILE *busf = tmpfile(); assert(busf); + mc_bus = fileno(busf); + int r = fcntl(mc_bus, F_GETFL); assert(r >= 0); + r |= O_APPEND; + r = fcntl(mc_bus, F_SETFL, r); assert(r >= 0); + + r = pipe(mc_work); assert(!r); + + mc_workers = xmalloc(sizeof(*mc_workers) * ncpus); + for (w=0; w= 0); + if (!mc_workers[w].pid) { + mc_us = &mc_workers[w]; + close(mc_work[1]); + LPRINTF("worker %2d running", w); + mc_iterate_worker(); + exit(0); + } + } + + close(mc_work[0]); + + genpid = fork(); assert(genpid >= 0); + if (!genpid) { + LPRINTF("generator running"); + iterate(); + exit(0); + } + + close(mc_work[1]); + mc_awaitpid(-1, genpid); + for (w=0; w best) + set_best(msg); + mc_bus_read += sizeof(msg); + } +} + +static void multicore_found_new_best(void) { + if (!ncpus) return; + + if (mc_us /* might be master */) fprintf(stderr," w%-2d ",mc_us->w); + ssize_t wrote = write(mc_bus, &best, sizeof(best)); + assert(wrote == sizeof(best)); +} + +/*----- end of multicore support -----*/ + static AdjWord *xalloc_adjmatrix(void) { return xmalloc(sizeof(*adjmatrix)*n); } @@@ -336,7 -99,9 +340,9 @@@ static void prep(void) adjall = ~((~(AdjWord)0) << m); adjmatrix = xalloc_adjmatrix(); glp_term_out(GLP_OFF); - n_over_best = n / best; - weight = (int *)malloc(m*sizeof(int)); - for (int j = 0; j < m; j++) weight[j] = 0; + setlinebuf(stderr); ++ weight = calloc(sizeof(*weight), m); assert(weight); ++ n_over_best = INT_MAX; } static AdjWord one_adj_bit(int bitnum) { @@@ -597,9 -338,20 +603,21 @@@ static void iterate_recurse(int i, AdjW goto again; if (i == 0 && (adjmatrix[i] & (1+adjmatrix[i]))) goto again; + + for (int j = 0; j < m; j++) - if (adjmatrix[i] & (1 << j)) ++ if (adjmatrix[i] & one_adj_bit(j)) + weight[j]++; + for (int j = 0; j < m; j++) + if (weight[j] >= n_over_best) + goto takeout; + iterate_recurse(i+1, adjmatrix[i]); - takeout: ++ takeout: + for (int j = 0; j < m; j++) - if (adjmatrix[i] & (1 << j)) ++ if (adjmatrix[i] & one_adj_bit(j)) + weight[j]--; + again: if (adjmatrix[i] == adjall) return;