From d3b2b0f8b4bf6827a353090a5d71b58e37cf233d Mon Sep 17 00:00:00 2001
From: Joerg Stelzer <joerg.stelzer@cern.ch>
Date: Wed, 2 Sep 2020 14:06:47 +0200
Subject: [PATCH] Fix HLT prescaling when run on preloaded data with
HLTEventLoopMgr forcedSORTime
---
.../TrigSteer/L1Decoder/src/PrescalingTool.cxx | 15 ++++++++++++++-
Trigger/TrigSteer/L1Decoder/src/PrescalingTool.h | 1 +
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.cxx b/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.cxx
index 1666340c73bf..458ba6cb56d7 100644
--- a/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.cxx
+++ b/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.cxx
@@ -6,6 +6,7 @@
#include "GaudiKernel/IToolSvc.h"
#include "CLHEP/Random/RandomEngine.h"
#include "CLHEP/Random/Ranlux64Engine.h"
+#include "xAODEventInfo/EventInfo.h"
const std::function< CLHEP::HepRandomEngine*(void) > PSTRanluxFactory = [](void)->CLHEP::HepRandomEngine*{
return new CLHEP::Ranlux64Engine();
@@ -25,6 +26,8 @@ StatusCode
PrescalingTool::initialize()
{
ATH_CHECK(m_hltPrescaleSetInputKey.initialize( ! m_hltPrescaleSetInputKey.key().empty() ));
+ ATH_CHECK( m_eventInfoKey.initialize() );
+
if ( !m_monTool.empty() ) ATH_CHECK(m_monTool.retrieve());
return StatusCode::SUCCESS;
@@ -68,7 +71,17 @@ StatusCode PrescalingTool::prescaleChains( const EventContext& ctx,
remainActive.reserve( initiallyActive.size() );
// create the seed from the event time
- size_t seed = ctx.eventID().time_stamp() ^ ctx.eventID().time_stamp_ns_offset();
+ /**
+ Note: the event time needs to be taken from the EventInfo instead EventContext.eventID, which is commonly done!
+ This is due to the special case when the trigger is run in a partition with preloaded data and the parameter @c
+ HLTEventLoopMgr.forceStartOfRunTime is set >0. In that case the @c EventContext.EventID is forced to the be the
+ SOR time for each event. Using the @c EventContext.eventID would lead to a constant seed and a scewed prescaling.
+ */
+ auto eventInfoHandle = SG::makeHandle( m_eventInfoKey, ctx );
+ CHECK( eventInfoHandle.isValid() );
+ size_t seed = eventInfoHandle->timeStamp() ^ eventInfoHandle->timeStampNSOffset();
+
+
CLHEP::HepRandomEngine* engine = m_RNGEngines.getEngine( ctx );
engine->setSeed( seed, 0 );
diff --git a/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.h b/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.h
index 313d3763a7d3..a7f57c120450 100644
--- a/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.h
+++ b/Trigger/TrigSteer/L1Decoder/src/PrescalingTool.h
@@ -59,6 +59,7 @@ class PrescalingTool : public extends<AthAlgTool, IPrescalingTool> {
// input data
SG::ReadCondHandleKey<TrigConf::HLTPrescalesSet> m_hltPrescaleSetInputKey{ this, "HLTPrescales", "HLTPrescales", "HLT prescales set"};
+ SG::ReadHandleKey<xAOD::EventInfo> m_eventInfoKey{ this, "EventInfo", "EventInfo", "Event Info Object Key"};
// properties
Gaudi::Property<bool> m_keepUnknownChains{ this, "KeepUnknownChains", true, "If True then chains for which prescaling information is not set are kept" };
--
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