Re: SGCL - Garbage Collector for C++

"Sebastian Nibisz" <EBA_K@poczta.onet.pl> wrote in message
news:fqmlgg$4cn$1@inews.gazeta.pl...


How you ensure proper memory visibility wrt an application thread's
operations on the buffer? The collector threads needs some kind of memory
synchronization with its mutators. Also, how is the buffer switching
different from real-time RCU with N=2 collector setup?

Can I do this:

___________________________________________________
static gc<int> g_val = gcnew int(0);

thread_writer() {
  gc<int> cmp, xchg = gcnew int;
  do {
    cmp = g_val;
    *xchg = (*cmp) + 1;
  } while (! g_val.cas_release(cmp, xchg));
  printf("inc %d to %d\n", *cmp, *xchg);
}

thread_reader() {
  gc<int> l_val = g_val;
  if (l_val) {
    printf("read %d\n", *l_val);
  }
}
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-- or --

___________________________________________________
template<typename T>
struct llnode {
  gc<llnode<T> > next;
  gc<T> state;
};

struct foo {
  typedef gc<llnode<foo> > gcptr;
};

static foo::gcptr g_list;

void llpush(foo::gcptr& n) {
  foo::gcptr cmp;
  do {
    n->next = cmp = g_list;
  } while (! g_list.cas_release(cmp, n));
}

bool llpop(foo::gcptr& ret) {
  foo::gcptr cmp, xchg;
  do {
    if (! (cmp = g_list)) {
      return false;
    }
    xchg = cmp->next;
  } while (! g_list.cas_acquire(cmp, xchg));
  ret = cmp;
  return true;
}
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I want to be able to do lock/wait-free programming with your smart pointer
interface. With proxy GC, I can use plain raw pointers for everything. How
is your scheme better than a proxy gc wrt creating non-blocking algorithms?

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