From 3669894446ad9a1a44290f06cb0ec73253e116f1 Mon Sep 17 00:00:00 2001
From: Hadrien Grasland <grasland@lal.in2p3.fr>
Date: Thu, 24 Jan 2019 18:53:06 +0100
Subject: [PATCH] Basic multi-slot backend
---
.../src/Conditions/ConditionBackendSvc.cpp | 46 +++++++++++++++++--
.../src/Conditions/ConditionBackendSvc.h | 32 +++++++++++--
.../src/Conditions/ConditionContext.cpp | 16 ++++++-
.../src/Conditions/ConditionContext.h | 23 ++++++----
4 files changed, 97 insertions(+), 20 deletions(-)
diff --git a/GaudiExamples/src/Conditions/ConditionBackendSvc.cpp b/GaudiExamples/src/Conditions/ConditionBackendSvc.cpp
index 316270189..c9e7d32f1 100644
--- a/GaudiExamples/src/Conditions/ConditionBackendSvc.cpp
+++ b/GaudiExamples/src/Conditions/ConditionBackendSvc.cpp
@@ -1,3 +1,4 @@
+#include <algorithm>
#include <stdexcept>
#include <unordered_map>
@@ -7,16 +8,33 @@ namespace DemoBackend
{
namespace detail
{
+ StatusCode ConditionBackendSvc::initialize()
+ {
+ auto status = Service::start();
+ if ( status.isFailure() ) return status;
+
+ m_slotUsage.reserve( m_numSlots );
+ for ( size_t i = 0; i < m_numSlots; ++i ) {
+ m_slotUsage.push_back( false );
+ }
+
+ return status;
+ }
+
void ConditionBackendSvc::registerCondition( Gaudi::ConditionAccessorBase& accessor )
{
if ( m_keysFrozen ) {
throw std::runtime_error( "Attempted to register a condition input after start()" );
}
+
if ( accessor.type() != typeid( float ) ) {
throw std::runtime_error( "This dummy condition back-end only supports float conditions" );
}
- auto res = m_data.emplace( accessor.key(), std::numeric_limits<float>::infinity() );
- const float* dataPtr = &( res.first->second );
+
+ std::vector<float> slots( m_numSlots, std::numeric_limits<float>::infinity() );
+ auto res = m_data.emplace( accessor.key(), std::move( slots ) );
+ const std::vector<float>* dataPtr = &( res.first->second );
+
auto id = reinterpret_cast<Gaudi::ConditionID>( dataPtr );
accessor.setID( id );
}
@@ -34,11 +52,17 @@ namespace DemoBackend
if ( !m_keysFrozen ) {
throw std::runtime_error( "Attempted to access a condition before start()" );
}
- std::unique_lock<std::mutex> dataLock( m_dataMutex );
+ size_t slotIdx = selectSlot( eventTime );
for ( auto& keyVal : m_data ) {
- keyVal.second = 4.2 * eventTime * keyVal.first.size();
+ keyVal.second[slotIdx] = 4.2 * eventTime * keyVal.first.size();
}
- return ConditionContext{ std::move( dataLock ) };
+ return ConditionContext{ *this, slotIdx };
+ }
+
+ void ConditionBackendSvc::releaseSlot( size_t slotIdx )
+ {
+ m_slotUsage[slotIdx] = false;
+ m_slotReady.notify_one();
}
const DataObjID& ConditionBackendSvc::contextPath() const
@@ -46,6 +70,18 @@ namespace DemoBackend
return m_contextPath;
}
+ size_t ConditionBackendSvc::selectSlot( const EventTimestamp& /* eventTime */ )
+ {
+ std::unique_lock<std::mutex> slotLock{ m_slotMutex };
+ auto slotIt = m_slotUsage.end();
+ m_slotReady.wait( slotLock, [&]{
+ slotIt = std::find( m_slotUsage.begin(), m_slotUsage.end(), false );
+ return slotIt != m_slotUsage.end();
+ } );
+ *slotIt = true;
+ return std::distance( m_slotUsage.begin(), slotIt );
+ }
+
DECLARE_COMPONENT( ConditionBackendSvc )
}
}
diff --git a/GaudiExamples/src/Conditions/ConditionBackendSvc.h b/GaudiExamples/src/Conditions/ConditionBackendSvc.h
index 9aca0bb10..24c3e44b8 100644
--- a/GaudiExamples/src/Conditions/ConditionBackendSvc.h
+++ b/GaudiExamples/src/Conditions/ConditionBackendSvc.h
@@ -1,7 +1,10 @@
#pragma once
+#include <condition_variable>
+#include <mutex>
#include <typeinfo>
-#include <unordered_set>
+#include <unordered_map>
+#include <vector>
#include "GaudiKernel/ConditionAccessorBase.h"
#include "GaudiKernel/ConditionKey.h"
@@ -36,6 +39,9 @@ namespace DemoBackend
// Inherited Service constructor
using Service::Service;
+ // Need to do some bookkeeping once amount of condition slots is known
+ StatusCode initialize() override;
+
// Notify the storage back-end that we will be accessing a condition
// Type info is provided to be able to type-check the condition dataflow
void registerCondition( Gaudi::ConditionAccessorBase& );
@@ -48,6 +54,9 @@ namespace DemoBackend
// derivation or gives access to previously prepared conditions.
ConditionContext setupEvent( const EventTimestamp& );
+ // ConditionContext implementation detail for releasing a storage slot
+ void releaseSlot( size_t slotIdx );
+
// TES location at which the condition context should be inserted
const DataObjID& contextPath() const;
@@ -56,12 +65,27 @@ namespace DemoBackend
Gaudi::Property<DataObjID> m_contextPath{
this, "ContextPath", "/Event/DemoBackendCondCtx", "Path to condition context in TES" };
+ // Number of condition storage slots to be used
+ Gaudi::Property<size_t> m_numSlots{
+ this, "StorageSlots", 4, "Number of condition storage slots to use" };
+
// Flag indicating when the above set can be considered complete
bool m_keysFrozen = false;
- // Condition storage
- std::mutex m_dataMutex;
- std::unordered_map<Gaudi::ConditionKey, float> m_data;
+ // Slots are shared mutable state, so access to them must be synchronized
+ std::mutex m_slotMutex;
+ std::condition_variable m_slotReady;
+
+ // One entry per storage slot, indicates if the slot is used
+ // FIXME: Use LRU eviction policy instead of first-fit
+ std::vector<bool> m_slotUsage;
+
+ // Condition data sorted by condition, one entry per storage slot
+ // FIXME: Have a single array of conditions to reduce allocation & memory spread
+ std::unordered_map<Gaudi::ConditionKey, std::vector<float>> m_data;
+
+ // Select a storage slot for an incoming event
+ size_t selectSlot( const EventTimestamp& );
};
}
}
\ No newline at end of file
diff --git a/GaudiExamples/src/Conditions/ConditionContext.cpp b/GaudiExamples/src/Conditions/ConditionContext.cpp
index 0c55574ad..64af4aedf 100644
--- a/GaudiExamples/src/Conditions/ConditionContext.cpp
+++ b/GaudiExamples/src/Conditions/ConditionContext.cpp
@@ -1,8 +1,20 @@
+#include "ConditionBackendSvc.h"
#include "ConditionContext.h"
namespace DemoBackend
{
- ConditionContext::ConditionContext( std::unique_lock<std::mutex>&& dataLock )
- : m_dataLock{ std::move( dataLock ) }
+ ConditionContext::~ConditionContext()
+ {
+ if ( m_backendSvc ) m_backendSvc->releaseSlot( m_slotIdx );
+ }
+
+ ConditionContext::ConditionContext( ConditionContext&& other )
+ : m_backendSvc{ std::exchange( other.m_backendSvc, nullptr ) }
+ , m_slotIdx{ other.m_slotIdx }
+ {}
+
+ ConditionContext::ConditionContext( detail::ConditionBackendSvc& backendSvc, size_t slotIdx )
+ : m_backendSvc{ &backendSvc }
+ , m_slotIdx{ slotIdx }
{}
}
\ No newline at end of file
diff --git a/GaudiExamples/src/Conditions/ConditionContext.h b/GaudiExamples/src/Conditions/ConditionContext.h
index 4a3249df1..a174276fe 100644
--- a/GaudiExamples/src/Conditions/ConditionContext.h
+++ b/GaudiExamples/src/Conditions/ConditionContext.h
@@ -3,6 +3,7 @@
#include <mutex>
#include <stdexcept>
#include <typeinfo>
+#include <vector>
#include "GaudiKernel/DataObject.h"
#include "GaudiKernel/ConditionID.h"
@@ -24,12 +25,13 @@ namespace DemoBackend
{
public:
// Upon going out of scope the ConditionContext will mark the conditions as unused
- ~ConditionContext() = default;
+ ~ConditionContext();
- // The ConditionContext is movable but not copyable
- ConditionContext( ConditionContext&& ) = default;
+ // The ConditionContext should be neither moved nor copied, but we can't
+ // prevent you from moving it until C++17 is the norm
+ ConditionContext( ConditionContext&& );
ConditionContext( const ConditionContext& ) = delete;
- ConditionContext& operator=( ConditionContext&& ) = default;
+ ConditionContext& operator=( ConditionContext&& ) = delete;
ConditionContext& operator=( const ConditionContext& ) = delete;
private:
@@ -44,8 +46,8 @@ namespace DemoBackend
if ( typeid( ConditionType ) != typeid( float ) ) {
throw std::runtime_error( "This silly backend only supports float conditions" );
}
- auto dataPtr = reinterpret_cast<const float*>( id );
- return *dataPtr;
+ auto dataPtr = reinterpret_cast<const std::vector<float>*>( id );
+ return (*dataPtr)[m_slotIdx];
}
private:
@@ -53,10 +55,13 @@ namespace DemoBackend
friend class detail::ConditionBackendSvc;
// Construct a ConditionContext from backend-internal data
- ConditionContext( std::unique_lock<std::mutex>&& dataLock );
+ ConditionContext( detail::ConditionBackendSvc& backend, size_t slotIdx );
private:
- // This silly implementation is actually locking
- std::unique_lock<std::mutex> m_dataLock;
+ // Must tell the ConditionBackendSvc to release our slot when destroyed
+ detail::ConditionBackendSvc* m_backendSvc;
+
+ // This is the condition slot index that we shall be targeting
+ size_t m_slotIdx;
};
}
\ No newline at end of file
--
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