ref: a3b9243f715e772329e7829c6778168e7e443a86
dir: /sys/src/games/galaxy/simulate.c/
#include <u.h> #include <libc.h> #include <draw.h> #include <thread.h> #include "galaxy.h" int extraproc = -1, throttle; static QLock *golock; static Rendez *gorend; static int *go; static QLock runninglock; static Rendez runningrend; static int running; static void calcproc(void *v) { Body *b, *e; int nbody; int pid; pid = (uintptr)v; for(;;) { qlock(golock+pid); while(!go[pid]) rsleep(gorend+pid); go[pid] = 0; qunlock(golock+pid); nbody = glxy.nb / (extraproc+1); b = glxy.a + nbody * pid; e = b + nbody; while(b < e) { b->a.x = b->newa.x; b->a.y = b->newa.y; b->newa.x = b->newa.y = 0; quadcalc(b++, space, LIM); } qlock(&runninglock); if(--running == 0) rwakeup(&runningrend); qunlock(&runninglock); } } static void startprocs(void) { int pid; golock = calloc(extraproc, sizeof(*golock)); if(golock == nil) sysfatal("Could not create go locks: %r\n"); gorend = calloc(extraproc, sizeof(*gorend)); if(gorend == nil) sysfatal("Could not create go rendez: %r\n"); go = calloc(extraproc, sizeof(*go)); if(go == nil) sysfatal("Could not create go flags: %r\n"); for(pid = 0; pid < extraproc; pid++) gorend[pid].l = golock+pid; runningrend.l = &runninglock; for(pid = 0; pid < extraproc; pid++) proccreate(calcproc, (void*)pid, STK); } /* verlet barnes-hut */ void simulate(void*) { Body *b, *s; int nbody, pid; double f; threadsetname("simulate"); startprocs(); for(;;) { qlock(&glxy); if(throttle) sleep(throttle); drawglxy(); Again: space.t = EMPTY; quads.l = 0; STATS(quaddepth = 0;) for(b = glxy.a; b < glxy.a + glxy.nb; b++) { if(quadins(b, LIM) == -1) { growquads(); goto Again; } } running = extraproc; for(pid = 0; pid < extraproc; pid++) { qlock(golock+pid); go[pid] = 1; rwakeup(gorend+pid); qunlock(golock+pid); } STATS(avgcalcs = 0;) nbody = glxy.nb / (extraproc+1); s = glxy.a + nbody * (extraproc); for(b = s; b < glxy.a + glxy.nb; b++) { b->a.x = b->newa.x; b->a.y = b->newa.y; b->newa.x = b->newa.y = 0; STATS(calcs = 0;) quadcalc(b, space, LIM); STATS(avgcalcs += calcs;) } STATS(avgcalcs /= glxy.nb;) qlock(&runninglock); while(running > 0) rsleep(&runningrend); qunlock(&runninglock); for(b = glxy.a; b < glxy.a + glxy.nb; b++) { b->x += dt*b->v.x + dt²*b->a.x/2; b->y += dt*b->v.y + dt²*b->a.y/2; b->v.x += dt*(b->a.x + b->newa.x)/2; b->v.y += dt*(b->a.y + b->newa.y)/2; CHECKLIM(b, f); } qunlock(&glxy); } }