parallel.c

   1 /*
   2  * Parallel processing
   3  */
   4
   5 #include <pthread.h>
   6
   7 #include "mgraph.h"
   8 #include "parallel.h"
   9
  10 typedef struct {
  11   const struct Vertices *vertices;
  12   Computation *separately;
  13   void *gendata;
  14 } ForAllThreads;
  15
  16 typedef struct {
  17   ForAllThreads *allthreads;
  18   int section;
  19   void *secdata;
  20   pthread_t thread;
  21 } PerThread;
  22
  23 static void *routine(void *thread_v) {
  24   PerThread *t= thread_v;
  25   ForAllThreads *a= t->allthreads;
  26
  27   a->separately(a->vertices, t->section, t->secdata, a->gendata);
  28
  29   return 0;
  30 }
  31
  32 void inparallel(const struct Vertices *vertices,
  33                 Computation *separately,
  34                 Computation *combine,
  35                 size_t secdatasz, void *gendata) {
  36   typedef struct { unsigned char secdata[secdatasz]; } SecData;
  37
  38   ForAllThreads allthreads;
  39   SecData secdatas[nsections];
  40   PerThread threads[nsections];
  41
  42   int s, r;
  43
  44   allthreads.vertices= vertices;
  45   allthreads.separately= separately;
  46   allthreads.gendata= gendata;
  47
  48   for (s=0; s<nsections; s++) {
  49     threads[s].allthreads= &allthreads;
  50     threads[s].section= s;
  51     threads[s].secdata= secdatas[s].secdata;
  52     r= pthread_create(&threads[s].thread,0,routine,&threads[s]);
  53     if (r) diee("pthread_create");
  54   }
  55
  56   for (s=0; s<nsections; s++) {
  57     r= pthread_join(threads[s].thread, 0);
  58     if (r) diee("pthread_join");
  59     combine(vertices, s, threads[s].secdata, gendata);
  60   }
  61 }