Home Research Papers Posters Manuals Talks Download People Help Internal

ck-ldb/NullLB.C

Go to the documentation of this file.

#include "NullLB.h"
#include "ck.h"

#define NULLLB_CONVERSE                     1

extern int quietModeRequested;

void CreateNullLB(void) {
  // special seqno -1
  // not putting into LBDatabase's loadbalancer list
  CProxy_NullLB::ckNew(-1);
}

static CkGroupID  _theNullLB;

#if NULLLB_CONVERSE
static int _migDoneHandle;      // converse handler
// converse handler 
// send converse message to avoid QD detection
static void migrationDone(envelope *env, CkCoreState *ck)
{
  // Since migrationsDone will deal with Charm++ messages,
  // the LB must obey the CkMessageWatcher orders.
  if (ck->watcher!=NULL) {
    if (!ck->watcher->processMessage(&env,ck)) return;
  }
  
  NullLB *lb = (NullLB*)CkLocalBranch(_theNullLB);
  lb->migrationsDone();
  CkFreeSysMsg(EnvToUsr(env));
}
#endif

static void lbinit(void) {
  LBRegisterBalancer("NullLB", CreateNullLB, NULL, "should not be shown", 0);
}

static void lbprocinit(void) {
#if NULLLB_CONVERSE
  CmiAssignOnce(&_migDoneHandle, CkRegisterHandlerEx(migrationDone, CkpvAccess(_coreState)));
#endif
}

#if CMK_LBDB_ON
static void staticStartLB(void* data)
{
  CmiPrintf("[%d] LB Info: StartLB called in NullLB.\n", CkMyPe());
}

void NullLB::init()
{
  // if (CkMyPe() == 0 && !quietModeRequested) CkPrintf("CharmLB> NullLB created.\n");
  thisProxy = CProxy_NullLB(thisgroup);
  CkpvAccess(hasNullLB) = 1;
  receiver = theLbdb->
    AddLocalBarrierReceiver((LDBarrierFn)(staticAtSync),
                (void*)(this));
  theLbdb->
    AddStartLBFn((LDStartLBFn)(staticStartLB),(void*)(this));

  if(CmiMyRank() == 0) _theNullLB = thisgroup;
}

NullLB::~NullLB()
{
  // the LBDatabase object may have been deleted.
  theLbdb = CProxy_LBDatabase(_lbdb).ckLocalBranch();
  if (theLbdb) {
    theLbdb->RemoveLocalBarrierReceiver(receiver);
    theLbdb->RemoveStartLBFn((LDStartLBFn)(staticStartLB));
  }
}

void NullLB::staticAtSync(void* data)
{
  // CmiPrintf("numLoadBalancers = %d\n", CkpvAccess(numLoadBalancers));
  if (CkpvAccess(numLoadBalancers) > 1) return;

  NullLB *me = (NullLB*)(data);
  me->AtSync();
}

// CkMigratable::AtSync() bypasses this to avoid waiting for LBPeriod
// when no balancer exists
void NullLB::AtSync()
{
  // tried to reset the database so it doesn't waste memory
  // if nobody else is here, the stat collection is not even turned on
  // so I should not have to clear loads.
//  theLbdb->ClearLoads();
  
  // disable the batsyncer if no balancer exists
  // theLbdb->SetLBPeriod(1e10);

#if ! NULLLB_CONVERSE
  // prevent this charm message from being seen by QD
  // so that the QD detection works
  CpvAccess(_qd)->create(-1);
  thisProxy[CkMyPe()].migrationsDone();
#else
  // send converse message to escape the QD detection
  envelope *env = UsrToEnv(CkAllocSysMsg());
  CmiSetHandler(env, _migDoneHandle);
  CmiSyncSendAndFree(CkMyPe(), env->getTotalsize(), (char *)env);
#endif
}

void NullLB::migrationsDone(void)
{
#if ! NULLLB_CONVERSE
  // prevent this charm message from being seen by QD
  CpvAccess(_qd)->process(-1);
#endif
  theLbdb->ResumeClients();
}

#else
/*No load balancer-- still need definitions to prevent linker errors.
I sure wish we had #ifdefs in the .ci file-- then we could avoid all this.
*/
void NullLB::init(void) {}
NullLB::~NullLB() {}
void NullLB::staticAtSync(void* data) {}
void NullLB::AtSync() {}
void NullLB::migrationsDone(void) {}
#endif

#include "NullLB.def.h"

---