HLTPrescaler.cc

Go to the documentation of this file.

//
// HLTPrescaler
// ------------
//
//           04/25/2008 Philipp Schieferdecker <philipp.schieferdecker@cern.ch>


#include "FWCore/ParameterSet/interface/ConfigurationDescriptions.h"
#include "FWCore/Framework/interface/LuminosityBlock.h"
#include "FWCore/ServiceRegistry/interface/PathContext.h"
#include "FWCore/ServiceRegistry/interface/PlaceInPathContext.h"
#include "FWCore/ServiceRegistry/interface/ModuleCallingContext.h"
#include "FWCore/ServiceRegistry/interface/Service.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "DataFormats/L1GlobalTrigger/interface/L1GlobalTriggerReadoutRecord.h"
#include "DataFormats/HLTReco/interface/TriggerFilterObjectWithRefs.h"
#include "HLTrigger/HLTcore/interface/HLTPrescaler.h"

// initialize static member variables

const unsigned int HLTPrescaler::prescaleSeed_ = 65537;

// construction/destruction

//_____________________________________________________________________________
HLTPrescaler::HLTPrescaler(edm::ParameterSet const& iConfig, const trigger::Efficiency* efficiency) :
  prescaleSet_(0)
  , prescaleFactor_(1)
  , eventCount_(0)
  , acceptCount_(0)
  , offsetCount_(0)
  , offsetPhase_(iConfig.getParameter<unsigned int>("offset"))
  , prescaleService_(0)
  , newLumi_(true)
  , gtDigiTag_ (iConfig.getParameter<edm::InputTag>("L1GtReadoutRecordTag"))
  , gtDigiToken_ (consumes<L1GlobalTriggerReadoutRecord>(gtDigiTag_))
{
  if(edm::Service<edm::service::PrescaleService>().isAvailable())
    prescaleService_ = edm::Service<edm::service::PrescaleService>().operator->();
  else 
    LogDebug("NoPrescaleService")<<"PrescaleService unavailable, prescaleFactor=1!";
}

//_____________________________________________________________________________    
HLTPrescaler::~HLTPrescaler()
{
  
}

// implementation of member functions

void HLTPrescaler::fillDescriptions(edm::ConfigurationDescriptions& descriptions) {
  edm::ParameterSetDescription desc;
  desc.add<unsigned int>("offset",0);
  desc.add<edm::InputTag>("L1GtReadoutRecordTag",edm::InputTag("hltGtDigis"));
  descriptions.add("hltPrescaler", desc);
}

//______________________________________________________________________________
void HLTPrescaler::beginLuminosityBlock(edm::LuminosityBlock const& lb,
                    edm::EventSetup const& iSetup)
{
  newLumi_ = true;
}


//_____________________________________________________________________________
bool HLTPrescaler::filter(edm::Event& iEvent, const edm::EventSetup&)
{
  // during the first event of a LumiSection, read from the GT the prescale index for this
  // LumiSection and get the corresponding prescale factor from the PrescaleService
  if (newLumi_) {
    newLumi_ = false;

    bool needsInit (eventCount_==0);

    if (prescaleService_) {
      std::string const & pathName = iEvent.moduleCallingContext()->placeInPathContext()->pathContext()->pathName();
      const unsigned int oldSet(prescaleSet_);
      const unsigned int oldPrescale(prescaleFactor_);

      edm::Handle<L1GlobalTriggerReadoutRecord> handle;
      iEvent.getByToken(gtDigiToken_,handle);
      if (handle.isValid()) {
        prescaleSet_ = handle->gtFdlWord().gtPrescaleFactorIndexAlgo();
        // gtPrescaleFactorIndexTech() is also available
        // by construction, they should always return the same index
        prescaleFactor_ = prescaleService_->getPrescale(prescaleSet_, pathName);
      } else {
        edm::LogWarning("HLT") << "Cannot read prescale column index from GT data: using default as defined by configuration or DAQ";
        prescaleFactor_ = prescaleService_->getPrescale(pathName);
      }

      if (prescaleSet_ != oldSet) {
        edm::LogInfo("ChangedPrescale")
          << "lumiBlockNb = " << iEvent.getLuminosityBlock().id().luminosityBlock()
      << ", set = " << prescaleSet_ << " [" << oldSet <<"]" 
          << ", path = "<< pathName
      << ": " << prescaleFactor_ << " [" <<oldPrescale<<"]";
        // reset the prescale counter
        needsInit = true;
      }
    }

    if (needsInit && (prescaleFactor_ != 0)) {
      // initialize the prescale counter to the first event number multiplied by a big "seed"
      offsetCount_ = ((uint64_t) (iEvent.id().event() + offsetPhase_) * prescaleSeed_) % prescaleFactor_;
    }
  }

  const bool result ( (prescaleFactor_ == 0) ? 
              false : ((eventCount_ + offsetCount_) % prescaleFactor_ == 0) );

  ++eventCount_;
  if (result) ++acceptCount_;
  return result;
}


//_____________________________________________________________________________
void HLTPrescaler::endStream()
{
  //since these are std::atomic, it is safe to increment them
  // even if multiple endStreams are being called.
  globalCache()->eventCount_ += eventCount_;
  globalCache()->acceptCount_ += acceptCount_; 
  return;
}

//_____________________________________________________________________________
void HLTPrescaler::globalEndJob(const trigger::Efficiency* efficiency)
{
  unsigned int accept(efficiency->acceptCount_);
  unsigned int event (efficiency->eventCount_);
  edm::LogInfo("PrescaleSummary")
    << accept << "/" << event
    << " ("
    << 100.*accept/static_cast<double>(std::max(1u,event))
    << "% of events accepted).";
  return;
}

#include "FWCore/Framework/interface/MakerMacros.h"
DEFINE_FWK_MODULE(HLTPrescaler);