diff options
Diffstat (limited to 'imc/libimc/master.c')
| -rw-r--r-- | imc/libimc/master.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/imc/libimc/master.c b/imc/libimc/master.c new file mode 100644 index 0000000..6d48b28 --- /dev/null +++ b/imc/libimc/master.c @@ -0,0 +1,180 @@ +#include "_libimc.h" +#include <stdio.h> +#include <time.h> +#include <assert.h> +#include <string.h> +#include <stdlib.h> +#include <stddef.h> +#include <unistd.h> +#include <signal.h> +#include <sys/wait.h> +#include <sys/prctl.h> + +int MASTER2WORKER_RD[N_WORKERS]; +int MASTER2WORKER_WR[N_WORKERS]; +int WORKER2MASTER_RD[N_WORKERS]; +int WORKER2MASTER_WR[N_WORKERS]; + +static size_t N_BRANCHES[N_WORKERS]; +static size_t N_BUGS[N_WORKERS]; +void handle_progress(struct message message, int worker_id) { + N_BRANCHES[worker_id] += message.n_branches; + N_BUGS[worker_id] += message.n_bugs; +} + +void print_progress(void) { + size_t total_branches = 0, total_bugs = 0; + printf("# branches:"); + for (int i = 0; i < N_WORKERS; i++) { + printf(" %lu", N_BRANCHES[i]); + total_branches += N_BRANCHES[i]; + } + printf("\n"); + printf("# bugs:"); + for (int i = 0; i < N_WORKERS; i++) { + printf(" %lu", N_BUGS[i]); + total_bugs += N_BUGS[i]; + } + printf("\n"); + printf("TOTAL branches: %lu; bugs: %lu\n", total_branches, total_bugs); +} + +void launch_master() { + // make a bugs directory + system("mkdir -p bugs"); + system("rm bugs/*"); + + assert(!prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0)); + + // set up the control pipes + for (int i = 0; i < N_WORKERS; i++) { + int ends[2]; + pipe2(ends, O_NONBLOCK); + MASTER2WORKER_RD[i] = ends[0]; + MASTER2WORKER_WR[i] = ends[1]; + pipe2(ends, O_NONBLOCK); + WORKER2MASTER_RD[i] = ends[0]; + WORKER2MASTER_WR[i] = ends[1]; + } + + // 0 -> dead, 1 -> alive, -1 -> waiting on it to die + int worker_alive[N_WORKERS] = {0}; + // only guaranteed to be up-to-date for workers with worker_alive[i] == -1 + int worker_pid[N_WORKERS] = {0}; + size_t dead_count = 0; + + // launch an initial worker + if (!fork()) { + launch_worker(0); + exit(0); + } + + worker_alive[0] = 1; + while (1) { + static time_t last_time = 0; + if ((time(0) - last_time) > 1) { + last_time = time(0); + print_progress(); + } + + // First: handle any workers that want to die + for (int i = 0; i < N_WORKERS; i++) { + if (!worker_alive[i]) continue; + if (worker_alive[i] == -1) { + if (waitpid(worker_pid[i], NULL, WNOHANG)) { + worker_alive[i] = 0; + clear_pipe(MASTER2WORKER_RD[i]); + clear_pipe(WORKER2MASTER_RD[i]); + } + continue; + } + + struct message message = hear_worker(i); + switch (message.message_type) { + case MSG_CAN_I_DIE: + worker_alive[i] = -1; + worker_pid[i] = message.pid; + verbose("Telling worker %d (%d) they can die\n", i, message.pid); + tell_worker((struct message){MSG_OK_DIE, 0}, i); + break; + + case MSG_PROGRESS: + handle_progress(message, i); + break; + + case MSG_NONE: + break; + + default: + assert(!"Bad message!"); + break; + } + } + + // Second: if we have empty slots, ask a worker to split. + int n_alive = 0, fill_slot = 0; + for (int i = 0; i < N_WORKERS; i++) { + n_alive += (worker_alive[i] != 0); + if (!worker_alive[i]) fill_slot = i; + } + if (n_alive == 0) break; + if (n_alive == N_WORKERS) continue; + + int which = rand() % n_alive; + for (int i = 0; i < N_WORKERS; i++) { + if (!worker_alive[i]) continue; + if (which--) continue; + if (worker_alive[i] == -1) continue; + + verbose("Requesting a split of %d -> %d\n", i, fill_slot); + tell_worker((struct message){ + .message_type = MSG_PLEASE_SPLIT, + .new_id = fill_slot + }, i); + + while (1) { + struct message reply = hear_worker(i); + switch (reply.message_type) { + case MSG_CAN_I_DIE: + verbose("Telling worker %d not to die, because we want to split\n"); + tell_worker((struct message){MSG_NO_DIE}, i); + break; + + case MSG_DID_SPLIT: + worker_alive[fill_slot] = 1; + waitpid(reply.pid, NULL, 0); + goto finish_split; + + case MSG_NO_SPLIT: + goto finish_split; + + case MSG_PROGRESS: + handle_progress(reply, i); + break; + + case MSG_NONE: + break; + + default: + printf("Unknown message %d!\n", reply.message_type); + break; + } + } + +finish_split: break; + } + } + + printf("Done with exhaustive search.\n"); + print_progress(); +} + +int main(int argc, char **argv) { + if (argc > 1) { + assert(argc == 2); + worker_replay(argv[1]); + } else { + launch_master(); + } + return 0; +} |