TCanvas *c1;
TTimer *t;
void fr1() {
   if (gROOT->GetListOfFiles()->FindObject("hsi.root")) {
      gDirectory->ReadKeys();
      gDirectory->GetList()->Delete();
   } else {
      //TFile *file = TFile::Open("http://root.cern.ch/files/hsi.root");
      TFile *file = TFile::Open("hsi.root");
   }
   TNtuple *ntuple = (TNtuple*)gDirectory->Get("ntuple");
   if (ntuple) {
      c1->cd(1);
      Long64_t nentries = ntuple->GetEntries();
      //if (nentries >= 2500000) t->TurnOff();
      ntuple->Draw("pz","","",1000,nentries-1000);
      delete ntuple;
   }
   TH1 *hpx = (TH1*)gDirectory->Get("hpx");
   if (hpx) {
      c1->cd(2);
      hpx->Draw();
   }
   c1->Update();
}
void fr() {
   c1 = new TCanvas("c1","c1",10,10,1000,400);
   c1->Divide(2,1);
   t = new TTimer("fr1()",1000); //fr1 will be called every 1000ms
   t->TurnOn();
}