This product is made available subject to acceptance of the EPICS open source license.
-EPICS version 4 is a set of related products in the EPICS
-V4 control system programming environment:
-relatedDocumentsV4.html
-
For more information about EPICS generally, please refer to the home page of the Experimental Physics and Industrial + Control System.
-This is the 23-October-2015 version of of pvDatabaseCPP.
-This version is a complete implementation of what is described in this manual. -
The first step is to build pvDatabaseCPP as described in the next section.
-One of the examples is exampleServer. -It can be started either via a main program or as part of a V3 IOC. +
A separate project exampleCPP has examples for pvDatabaseCPP +and for pvaClientCPP. +See it for examples.
-To start it as a main program do the following:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleServer -mrk> bin/linux-x86_64/exampleServerMain --
You should see something like the following:
--result of addRecord exampleServer 1 -VERSION : pvAccess Server v3.0.5-SNAPSHOT -PROVIDER_NAMES : local -BEACON_ADDR_LIST : -AUTO_BEACON_ADDR_LIST : 1 -BEACON_PERIOD : 15 -BROADCAST_PORT : 5076 -SERVER_PORT : 5075 -RCV_BUFFER_SIZE : 16384 -IGNORE_ADDR_LIST: -STATE : INITIALIZED -exampleServer -Type exit to stop: --
Then in another window execute a pvput and pvget as follows:
--mrk> pvput -r "field(argument.value)" exampleServer World -... -mrk> pvget -r "record[process=true]field(result.value)" exampleServer -exampleServer -structure - string value Hello World -mrk> --
To run the example as part of a V3 IOC do the following:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleServer/iocBoot/exampleServer -mrk> ../../bin/linux-x86_64/exampleServer st.cmd --
You will see the following:
-
-> envPaths
-epicsEnvSet("ARCH","linux-x86_64")
-epicsEnvSet("IOC","exampleServer")
-epicsEnvSet("TOP","/home/hg/pvDatabaseCPP/exampleServer")
-epicsEnvSet("EPICS_BASE","/home/install/epics/base")
-epicsEnvSet("EPICSV4HOME","/home/hg")
-cd /home/hg/pvDatabaseCPP/exampleServer
-## Register all support components
-dbLoadDatabase("dbd/exampleServer.dbd")
-exampleServer_registerRecordDeviceDriver(pdbbase)
-## Load record instances
-dbLoadRecords("db/dbScalar.db","name=pvdouble,type=ao")
-dbLoadRecords("db/dbArray.db","name=pvdoubleArray,type=DOUBLE")
-dbLoadRecords("db/dbStringArray.db","name=pvstringArray")
-dbLoadRecords("db/dbEnum.db","name=pvenum")
-dbLoadRecords("db/dbCounter.db","name=pvcounter");
-cd /home/hg/pvDatabaseCPP/exampleServer/iocBoot/exampleServer
-iocInit()
-Starting iocInit
-############################################################################
-## EPICS R3.14.12.3 $Date: Mon 2012-12-17 14:11:47 -0600$
-## EPICS Base built Dec 21 2013
-############################################################################
-iocRun: All initialization complete
-dbl
-pvdouble
-pvcounter
-pvenum
-pvdoubleArray
-pvstringArray
-epicsThreadSleep(1.0)
-exampleServerCreateRecord pvaServer
-startPVAServer
-VERSION : pvAccess Server v3.0.5-SNAPSHOT
-PROVIDER_NAMES : dbPv local
-BEACON_ADDR_LIST :
-AUTO_BEACON_ADDR_LIST : 1
-BEACON_PERIOD : 15
-BROADCAST_PORT : 5076
-SERVER_PORT : 5075
-RCV_BUFFER_SIZE : 16384
-IGNORE_ADDR_LIST:
-STATE : INITIALIZED
-pvdbl
-pvaServer
-epics>
-
-Just like previously you can then execute a pvput and pvget and see Hello World. -
-The examples, i. e. exampleServer, exampleLink, examplePowerSupply, -and exampleDatabase, are described in separate sections below. -In addition arrayPerformance can be used to measure that performance of big -arrays. It is also described in a later section.
-Reading section exampleServer and looking at it's code is a good way -to learn how to implement a service.
mrk> cd .. mrk> pwd -/home/hg/pvDatabaseCPP +/home/epicsv4/master/pvDatabaseCPP mrk> make-
This builds pvDatabaseCPP and also the tests and all examples.
-Each example and arrayPerformance is a completely separate top, +
This builds pvDatabase and also test.
+test is a completely separate top, but is also built when make is run in pvDatabaseCPP itself.
--Each is a separate top for the following reasons:
--If it is desired to build an example all by itself, -just follow the same instructions as for building pvDatabaseCPP itself. -For example:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleServer/configure -mrk> cp ExampleRELEASE.local RELEASE.local --
Then edit RELEASE.local so that it has the correct location of each -product the example requires. -Than at the top level of the example just execute make:
--mrk> cd .. -mrk> pwd -/home/hg/pvDatabaseCPP/exampleServer -mrk> make --
This builds the example.
Shell commands are made available via the standard DBD include mechanism provided by iocCore. The following provide EPICS V4 shell commands:
--Look at exampleServer/ioc/src/exampleServerInclude.dbd for an example -of how an application can make the shell commands available. -
-The following iocsh commands are provided for a V3IOC:
-+pvAccessCPP +pvaSrv +pvDatabaseCPP +-
The following iocsh commands are provided for a V3IOC:
+pvDatabaseCPP provides the following iocshell command.
In addition any code that implements a PVRecord must implement an ioc command. -Look at any of the examples to see how to implement shell commands.
-pvaSrv provides a pvAccess server that provides access to iocCore records.
-pvaSrv does not provide any shell commands but it can be part of an IOC. -Just make sure your application configures pvaSrv and then include the following file: -
--include "dbPv.dbd" -+Look at any of the examples in exampleCPP to see how to implement shell commands.
The example implements a simple service that has a top level pvStructure: -
--structure - structure argument - string value - structure result - string value - time_t timeStamp - long secondsPastEpoch - int nanoseconds - int userTag --
It is designed to be accessed via a channelPutGet request. -The client sets argument.value -When the record processes it sets result.value to "Hello " -concatenated with argument.value. -Thus if the client sets argument.value equal to "World" -result.value will be "Hello World". -In addition the timeStamp is set to the time when process is called.
--The example can be run on linux as follows:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleService -mrk> bin/linux-x86_64/exampleService --
-The directory layout is: -
--exampleServer - configure - ExampleRELEASE.local - ... - src - exampleServer.h - exampleServer.cpp - exampleServerInclude.dbd - exampleServerMain.cpp - exampleServerRegister.cpp - exampleServerRegister.dbd - ioc - Db - ... - src - exampleServerInclude.dbd - exampleServerMain.cpp - iocBoot - exampleServer - st.cmd - ... --where -
-exampleServerCreateRecord exampleServer -- Multiple commands can be issued to create multiple service records. -
If only a main program is desired then the directory layout is:
--exampleServer - configure - ExampleRELEASE.local - ... - src - exampleServer.h - exampleServer.cpp - exampleServerMain.cpp --
Thus if only a main program is required the directory layout is simple.
-Also many sites will want to build the src directory in an area -separate from where the iocs are build.
-The example resides in src -The implementation is in exampleServer.cpp. -
-The description consists of
-
-class ExampleServer;
-typedef std::tr1::shared_ptr<ExampleServer> ExampleServerPtr;
-
-class ExampleServer :
- public PVRecord
-{
-public:
- POINTER_DEFINITIONS(ExampleServer);
- static ExampleServerPtr create(
- std::string const & recordName);
- virtual ~ExampleServer();
- virtual void destroy();
- virtual bool init();
- virtual void process();
-private:
- ExampleServer(std::string const & recordName,
- epics::pvData::PVStructurePtr const & pvStructure);
-
- epics::pvData::PVStringPtr pvArgumentValue;
- epics::pvData::PVStringPtr pvResultValue;
- epics::pvData::PVTimeStamp pvTimeStamp;
- epics::pvData::TimeStamp timeStamp;
-};
-
-where
-The implementation of create method is:
-
-ExampleServerPtr ExampleServer::create(
- std::string const & recordName)
-{
- StandardFieldPtr standardField = getStandardField();
- FieldCreatePtr fieldCreate = getFieldCreate();
- PVDataCreatePtr pvDataCreate = getPVDataCreate();
- StructureConstPtr topStructure = fieldCreate->createFieldBuilder()->
- addNestedStructure("argument")->
- add("value",pvString)->
- endNested()->
- addNestedStructure("result") ->
- add("value",pvString) ->
- add("timeStamp",standardField->timeStamp()) ->
- endNested()->
- createStructure();
- PVStructurePtr pvStructure = pvDataCreate->createPVStructure(topStructure);
-
- ExampleServerPtr pvRecord(
- new ExampleServer(recordName,pvStructure));
- if(!pvRecord->init()) pvRecord.reset();
- return pvRecord;
-}
-
-This:
-The private constructor method is:
-
-ExampleServer::ExampleServer(
- std::string const & recordName,
- epics::pvData::PVStructurePtr const & pvStructure)
-: PVRecord(recordName,pvStructure)
-{
-}
-
-The example is very simple. Note that it calls the base class constructor.
-The destructor and destroy methods are:
-
-ExampleServer::~ExampleServer()
-{
-}
-
-void ExampleServer::destroy()
-{
- PVRecord::destroy();
-}
-
-The destructor has nothing to do.
-The destroy method, which is virtual, just calls the destroy method of the base class.
-A more complicated example can clean up any resources it used but must call the base
-class destroy method.
-The implementation of init is:
-
-bool ExampleServer::init()
-{
- initPVRecord();
- PVFieldPtr pvField;
- pvArgumentValue = getPVStructure()->getStringField("argument.value");
- if(pvArgumentValue.get()==NULL) return false;
- pvResultValue = getPVStructure()->getStringField("result.value");
- if(pvResultValue.get()==NULL) return false;
- pvTimeStamp.attach(getPVStructure()->getSubField("result.timeStamp"));
- return true;
-}
-
-The implementation of process is:
-
-void ExampleServer::process()
-{
- pvResultValue->put(String("Hello ") + pvArgumentValue->get());
- timeStamp.getCurrent();
- pvTimeStamp.set(timeStamp);
-}
-
-It gives a value to result.value and
-then sets the timeStamp to the current time.
-NOTE: -This is a shorter version of the actual code. -It shows the essential code. -The actual example shows how create an additional record. -
-The main program is:
-
-int main(int argc,char *argv[])
-{
- PVDatabasePtr master = PVDatabase::getMaster();
- ChannelProviderLocalPtr channelProvider = ChannelProviderLocal::create();
- String recordName("exampleServer");
- PVRecordPtr pvRecord = ExampleServer::create(recordName);
- bool result = master->addRecord(pvRecord);
- if(!result) cout<< "record " << recordName << " not added" << endl;
- recordName = "traceRecordPGRPC";
- pvRecord = TraceRecord::create(recordName);
- result = master->addRecord(pvRecord);
- if(!result) cout<< "record " << recordName << " not added" << endl;
- ServerContext::shared_pointer pvaServer =
- startPVAServer(PVACCESS_ALL_PROVIDERS,0,true,true);
- PVStringArrayPtr pvNames = master->getRecordNames();
- shared_vector<const string> names = pvNames->view();
- for(size_t i=0; i<names.size(); ++i) cout << names[i] << endl;
- string str;
- while(true) {
- cout << "Type exit to stop: \n";
-
- }
- return 0;
-}
-
-This:
-To start exampleServer as part of a V3IOC:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleServer/iocBoot/exampleServer -mrk> ../../../bin/linux-x86_64/exampleServer st.cmd --
You can then issue the commands dbl and pvdbl:
--epics> dbl -pvdouble -pvcounter -pvenum -pvdoubleArray -pvstringArray -epics> pvdbl -exampleServer -epics> --dbl shows the V3 records. -pvdbl shows the pvRecords. -
-It starts pvaSrv so that the V3 records can be accessed via Channel Access -or via PVAccess.
- -The exampleServer pvDatabase has many records including the following:
-It also has a number of other scalar and array records.
-exampleDatabase can be started as a main program or as a V3 IOIC. -If started as a V3 IOC it also has a number of V3 records, -and starts pvaSrv so that the V3 records can be accessed via Channel Access -or via PVAccess.
-This example show how a service can access other PVRecords. -This section 1) starts with a discussion of accessing data via pvAccess -and 2) gives a brief description of an example that gets data for an array of doubles.
-The process routine of a PVRecord can access other PVRecords in two ways:
-Access via pvAccess can be done either by local or remote channel provider.
-If pvAccess is used then it handles data synchronization. -This is done by making a copy of the data that is transferred between the two pvRecords. -This is true if either remote or local pvAccess is used. -Each get, put, etc request results in data being copied between the two records.
--If the linked channel is a local pvRecord then, -for scalar and structure arrays, -raw data is NOT copied for gets. -This is because pvData uses shared_vector to hold the raw data. -Instead of copying the raw data the reference count is incremented.
-For puts the linked array will force a new allocation of the raw data in the linked record, -i. e. copy on write semantics are enforced. This is done automatically -by pvData and not by pvDatabase.
-As mentioned before a pvDatabase server can be either a separate process, -i. e. a main program, or can be part of a V3IOC.
-A main pvDatabase server issues the following calls:
-- ClientFactory::start(); - ChannelProviderLocalPtr channelProvider = getChannelProviderLocal(); - ... - ServerContext::shared_pointer serverContext = - startPVAServer(PVACCESS_ALL_PROVIDERS,0,true,true); --
The first call is only necessary if some of the pvRecords -have pvAccess links. -These must be called before any code that uses links is initialized. -After these two calls there will be two channel providers: local, and pvAccess. - -
-A pvDatabase that is part of a V3IOC has the following in the st.cmd file.
--... -iocInit() -startPVAClient -startPVAServer -## commands to create pvRecords --
-Once the client and local provider code has started then the following creates a channel access link. -
--PVDatabasePtr master = PVDatabase::getMaster(); -ChannelProvider::shared_pointer provider = - getChannelProviderRegistry()->getProvider(providerName); -Channel::shared_pointer channel = provider->createChannel(channelName,channelRequester); -- -
-exampleLink - configure - ExampleRELEASE.local - ... - src - exampleLink.h - exampleLink.cpp - exampleLinkInclude.dbd - exampleLinkRegister.cpp - ioc - Db - src - exampleLinkInclude.dbd - exampleLinkMain.cpp - iocBoot - exampleLink - st.local - st.remote - ... --
This example is only built to be run as part of a V3 IOC. -Note that two startup files are available: st.local and st.remote. -st.local has two records: doubleArray and exampleLink. -doubleArray is a record that can be changed via a call to pvput. -exampleLink is a record that, when processed, gets the value from doubleArray and sets its value equal -to the value read. -st.local has both records. -st.remote has only one record named exampleLinkRemote. -
-To start the example:
--mrk> pwd -/home/hg/pvDatabaseCPP/exampleLink/iocBoot/exampleLink -mrk> ../../bin/linux-x86_64/exampleLink st.local --
then in another window:
--mrk> pvput doubleArray 4 100 200 300 400 -Old : doubleArray 0 -New : doubleArray 4 100 200 300 400 -mrk> pvget -r "record[process=true]field(value)" exampleLink -exampleLink -structure - double[] value [100,200,300,400] -mrk> --
exampleLink.h contains the following:
-
-...
-class ExampleLink :
- public PVRecord,
- public epics::pvAccess::ChannelRequester,
- public epics::pvAccess::ChannelGetRequester
-{
-public:
- POINTER_DEFINITIONS(ExampleLink);
- static ExampleLinkPtr create(
- std::string const & recordName,
- std::string const & providerName,
- std::string const & channelName
- );
- virtual ~ExampleLink() {}
- virtual void destroy();
- virtual bool init();
- virtual void process();
- virtual void channelCreated(
- const epics::pvData::Status& status,
- epics::pvAccess::Channel::shared_pointer const & channel);
- virtual void channelStateChange(
- epics::pvAccess::Channel::shared_pointer const & channel,
- epics::pvAccess::Channel::ConnectionState connectionState);
- virtual void channelGetConnect(
- const epics::pvData::Status& status,
- epics::pvAccess::ChannelGet::shared_pointer const & channelGet,
- epics::pvData::PVStructure::shared_pointer const & pvStructure,
- epics::pvData::BitSet::shared_pointer const & bitSet);
- virtual void getDone(const epics::pvData::Status& status);
-private:
-...
-
-All the non-static methods are either PVRecord, PVChannel, or PVChannelGet methods -and will not be discussed further. -The create method is called to create a new PVRecord instance with code that will issue -a ChannelGet::get request every time the process method of the instance is called. -Some other pvAccess client can issue a channelGet, to the record instance, with a request -to process in order to test the example.
-All of the initialization is done by a combination of the create and init methods so -lets look at them:
-
-ExampleLinkPtr ExampleLink::create(
- String const & recordName,
- String const & providerName,
- String const & channelName)
-{
- PVStructurePtr pvStructure = getStandardPVField()->scalarArray(
- pvDouble,"alarm.timeStamp");
- ExampleLinkPtr pvRecord(
- new ExampleLink(
- recordName,providerName,channelName,pvStructure));
- if(!pvRecord->init()) pvRecord.reset();
- return pvRecord;
-}
-
-This first creates a new ExampleLink instance, -and then calls the init method and the returns a ExampleLinkPtr. -Note that if init returns false it returns a pointer to NULL.
-The init method is:
-
-bool ExampleLink::init()
-{
- initPVRecord();
-
- PVStructurePtr pvStructure = getPVRecordStructure()->getPVStructure();
- pvTimeStamp.attach(pvStructure->getSubField("timeStamp"));
- pvAlarm.attach(pvStructure->getSubField("alarm"));
- pvValue = static_pointer_cast<PVDoubleArray>(
- pvStructure->getScalarArrayField("value",pvDouble));
- if(pvValue==NULL) {
- return false;
- }
- ChannelAccess::shared_pointer channelAccess = getChannelAccess();
- ChannelProvider::shared_pointer provider =
- channelAccess->getProvider(providerName);
- if(provider==NULL) {
- cout << getRecordName() << " provider "
- << providerName << " does not exist" << endl;
- return false;
- }
- ChannelRequester::shared_pointer channelRequester =
- dynamic_pointer_cast<ChannelRequester>(getPtrSelf());
- channel = provider->createChannel(channelName,channelRequester);
- event.wait();
- if(!status.isOK()) {
- cout << getRecordName() << " createChannel failed "
- << status.getMessage() << endl;
- return false;
- }
- ChannelGetRequester::shared_pointer channelGetRequester =
- dynamic_pointer_cast<ChannelGetRequester>(getPtrSelf());
- PVStructurePtr pvRequest = getCreateRequest()->createRequest(
- "value,alarm,timeStamp",getPtrSelf());
- channelGet = channel->createChannelGet(channelGetRequester,pvRequest);
- event.wait();
- if(!status.isOK()) {
- cout << getRecordName() << " createChannelGet failed "
- << status.getMessage() << endl;
- return false;
- }
- getPVValue = static_pointer_cast<PVDoubleArray>(
- getPVStructure->getScalarArrayField("value",pvDouble));
- if(getPVValue==NULL) {
- cout << getRecordName() << " get value not PVDoubleArray" << endl;
- return false;
- }
- return true;
-}
-
-This first makes sure the pvStructure has the fields it requires:
-Next it makes sure the channelProvider exists.
-Next it creates the channel and waits until it connects.
-Next it creates the channelGet and waits until it is created.
-Next it makes sure it has connected to a double array field.
-If anything goes wrong during initialization it returns false. -This a return of true means that it has successfully created a channelGet and is ready -to issue gets when process is called.
-Look at the code for more details.
-This is an example of creating a service that requires a somewhat complicated -top level PVStructure. -Look at the code for details. -
-This section describes main programs that demonstrate performance -of large arrays and can also be used to check for memory leaks. -Checking for memory leaks can be accomplished by running the programs with valgrind -or some other memory check program. -
-The programs are:
-Each has support for -help.
--mrk> pwd -/home/hg/pvDatabaseCPP-md -mrk> bin/linux-x86_64/arrayPerformanceMain -help -arrayPerformanceMain recordName size delay providerName nMonitor queueSize waitTime -default -arrayPerformanceMain arrayPerformance 10000000 0.0001 local 1 2 0.0 - -mrk> bin/linux-x86_64/longArrayMonitorMain -help -longArrayMonitorMain channelName queueSize waitTime -default -longArrayMonitorMain arrayPerformance 2 0.0 - -mrk> bin/linux-x86_64/longArrayGetMain -help -longArrayGetMain channelName iterBetweenCreateChannel iterBetweenCreateChannelGet delayTime -default -longArrayGetMain arrayPerformance 0 0 1 - -mrk> bin/linux-x86_64/longArrayPutMain -help -longArrayPutMain channelName arraySize iterBetweenCreateChannel iterBetweenCreateChannelPut delayTime -default -longArrayPutMain arrayPerformance 10 0 0 1 - -mrk> --
Note: These may fail if run on a platform that does not have sufficient memory,
-To see an example just execute the following commands in four different terminal windows:
--bin/linux/<arch>/arrayPerformanceMain -bin/linux/<arch>/longArrayMonitorMain -bin/linux/<arch>/longArrayGetMain -bin/linux/<arch>/longArrayPutMain --
Each program generates a report every second when it has something to report. -Examples are:
-
-mrk> bin/linux-x86_64/arrayPerformanceMain
-arrayPerformance arrayPerformance 10000000 0.0001 local 1 2 0
-...
- monitors/sec 66 first 131 last 131 changed {1, 2} overrun {} megaElements/sec 656.999
-arrayPerformance value 132 time 1.00486 Iterations/sec 65.681 megaElements/sec 656.81
- monitors/sec 66 first 197 last 197 changed {1, 2} overrun {} megaElements/sec 656.304
-arrayPerformance value 198 time 1.00563 Iterations/sec 65.6307 megaElements/sec 656.307
- monitors/sec 66 first 263 last 263 changed {1, 2} overrun {} megaElements/sec 654.824
-...
-
-
-mrk> bin/linux-x86_64/longArrayMonitorMain
-longArrayMonitorMain arrayPerformance 2 0
-...
- monitors/sec 6 first 2357 last 2357 changed {1, 2} overrun {} megaElements/sec 68.6406
- monitors/sec 13 first 2385 last 2385 changed {1, 2} overrun {} megaElements/sec 118.72
- monitors/sec 9 first 2418 last 2418 changed {1, 2} overrun {1, 2} megaElements/sec 85.0984
-...
-
--mrk> bin/linux-x86_64/longArrayPutMain -longArrayPutMain arrayPerformance 10 0 0 1 -... -put numChannelPut 0 time 1.00148 Elements/sec 79.8819 -put numChannelPut 1 time 1.00176 Elements/sec 79.8598 -... --
-mrk> bin/linux-x86_64/longArrayGetMain -longArrayGetMain arrayPerformance 0 0 1 -... -get kiloElements/sec 7384.61 -get kiloElements/sec 8726.34 -... -- -
The arguments for arrayPerforamanceMain are:
--arrayPerformance creates a PVRecord that has the structure:. -
--recordName - long[] value - timeStamp timeStamp - alarm alarm --Thus it holds an array of 64 bit integers. -
The record has support that consists of a separate thread that runs -until the record is destroyed executing the following algorithm:
-This is a pvAccess client that monitors an arrayPerformance record. -It generates a report every second showing how many elements has received. -For every monitor it also checks that the number of elements is >0 and the -the first element equals the last element. It reports an error if either -of these conditions is not true.
-The arguments for longArrayMonitorMain are:
-This is a pvAccess client that uses channelGet to access an arrayPerformance record. -Every second it produces a report.
- -The arguments for longArrayGetMain are:
-This is a pvAccess client that uses channelPut to access an arrayPerformance record. -Every second it produces a report.
- -The arguments for longArrayPutMain are:
-The results were from my laptop in 2013 -It had a 2.2Ghz intel core i7 with 4Gbytes of memory. -The operating system was linux fedora 16.
-When test are performed with large arrays it is a good idea to also -run a system monitor facility and check memory and swap history. -If a test configuration causes physical memory to be exhausted -then performance becomes very poor. -You do not want to do this.
-The simplest test to run arrayPerformance with the defaults:
--mrk> pwd -/home/hg/pvDatabaseCPP-md -mrk> bin/linux-x86_64/arrayPerformanceMain --
This means that the array will hold 10 million elements. -The delay will be a millisecond. -There will be a single monitor and it will connect directly -to the local channelProvider, i. e. it will not use any network -connection.
-The report shows that arrayPerformance can perform about 50 iterations per second -and is putting about 500million elements per second. -Since each element is an int64 this means about 4gigaBytes per second. -
-When no monitors are requested and a remote longArrayMonitorMain is run:
--mr> pwd -/home/hg/pvDatabaseCPP-md -mrk> bin/linux-x86_64/longArrayMonitorMain --
The performance drops to about 25 iterations per second and 250 million elements per second. -The next section has an example that demonstrates what happens. -Note that if the array size is small enough to fit in the local cache then running longArrayMonitor -has almost no effect of arrayPerforance. -
-Running longArrayMonitorMain, longArrayPutMain, and longArrayGetMain -under valgrind shows no memory leaks.
-arrayPerformanceMain shows the following:
--==9125== LEAK SUMMARY: -==9125== definitely lost: 0 bytes in 0 blocks -==9125== indirectly lost: 0 bytes in 0 blocks -==9125== possibly lost: 576 bytes in 2 blocks --
The possibly leaked is either 1 or 2 blocks. -It seems to be the same if clients are connected. -
-This example demonstrates how array size effects performance. -The example is run as:
--bin/linux-x86_64/vectorPerformanceMain -help -vectorPerformanceMain size delay nThread -default -vectorPerformance 50000000 0.01 1 --
Consider the following:
--bin/linux-x86_64/vectorPerformanceMain 50000000 0.00 1 -... -thread0 value 20 time 1.01897 iterations/sec 19.6277 elements/sec 981.383million -thread0 value 40 time 1.01238 iterations/sec 19.7554 elements/sec 987.772million -thread0 value 60 time 1.00878 iterations/sec 19.826 elements/sec 991.299million -... -bin/linux-x86_64/vectorPerformanceMain 50000000 0.00 2 -... -thread0 value 21 time 1.00917 iterations/sec 9.90911 elements/sec 495.455million -thread1 value 31 time 1.05659 iterations/sec 9.46443 elements/sec 473.221million -thread0 value 31 time 1.07683 iterations/sec 9.28648 elements/sec 464.324million -thread1 value 41 time 1.0108 iterations/sec 9.89312 elements/sec 494.656million -... -bin/linux-x86_64/vectorPerformanceMain 50000000 0.00 3 -thread0 value 7 time 1.0336 iterations/sec 6.77244 elements/sec 338.622million -thread1 value 7 time 1.03929 iterations/sec 6.73534 elements/sec 336.767million -thread2 value 7 time 1.04345 iterations/sec 6.70852 elements/sec 335.426million -thread0 value 14 time 1.03335 iterations/sec 6.77406 elements/sec 338.703million -thread1 value 14 time 1.03438 iterations/sec 6.76734 elements/sec 338.367million -thread2 value 14 time 1.04197 iterations/sec 6.71805 elements/sec 335.903million -... -bin/linux-x86_64/vectorPerformanceMain 50000000 0.00 4 -thread2 value 5 time 1.00746 iterations/sec 4.96298 elements/sec 248.149million -thread1 value 5 time 1.02722 iterations/sec 4.86751 elements/sec 243.376million -thread3 value 5 time 1.032 iterations/sec 4.84496 elements/sec 242.248million -thread0 value 6 time 1.18882 iterations/sec 5.04703 elements/sec 252.351million -thread2 value 10 time 1.00388 iterations/sec 4.98068 elements/sec 249.034million -thread3 value 10 time 1.02755 iterations/sec 4.86592 elements/sec 243.296million -thread1 value 10 time 1.04836 iterations/sec 4.76936 elements/sec 238.468million -thread0 value 11 time 1.01575 iterations/sec 4.92249 elements/sec 246.124million --
As more threads are running the slower each thread runs.
-But now consider a size that fits in a local cache.
--bin/linux-x86_64/vectorPerformanceMain 5000 0.00n/linux-x86_64/vectorPerformanceMain 5000 0.00 1 -... -thread0 value 283499 time 1 iterations/sec 283498 elements/sec 1417.49million -thread0 value 569654 time 1 iterations/sec 286154 elements/sec 1430.77million -thread0 value 856046 time 1 iterations/sec 286392 elements/sec 1431.96million -... -bin/linux-x86_64/vectorPerformanceMain 5000 0.00 2 -... -thread0 value 541790 time 1 iterations/sec 271513 elements/sec 1357.56million -thread1 value 541798 time 1 iterations/sec 271418 elements/sec 1357.09million -thread0 value 813833 time 1 iterations/sec 272043 elements/sec 1360.21million -thread1 value 813778 time 1 iterations/sec 271979 elements/sec 1359.89million -thread0 value 541790 time 1 iterations/sec 271513 elements/sec 1357.56million -thread1 value 541798 time 1 iterations/sec 271418 elements/sec 1357.09million -thread0 value 813833 time 1 iterations/sec 272043 elements/sec 1360.21million -thread1 value 813778 time 1 iterations/sec 271979 elements/sec 1359.89million -... -bin/linux-x86_64/vectorPerformanceMain 5000 0.00 3 -... -thread0 value 257090 time 1 iterations/sec 257089 elements/sec 1285.45million -thread1 value 256556 time 1 iterations/sec 256556 elements/sec 1282.78million -thread2 value 514269 time 1 iterations/sec 257839 elements/sec 1289.19million -thread0 value 514977 time 1 iterations/sec 257887 elements/sec 1289.43million -thread1 value 514119 time 1 iterations/sec 257563 elements/sec 1287.81million -thread2 value 770802 time 1 iterations/sec 256532 elements/sec 1282.66million --
Now the number of threads has a far smaller effect on the performance of each thread. -
This product is made available subject to acceptance of the EPICS open source license.
-This document describes pvDatabaseCPP, -which is a framework for implementing a network accessable database of smart memory resident -records. Network access is via pvAccess. The data in each record is a top level PVStructure as defined by -pvData. The framework includes a complete implementation of ChannelProvider as defined by pvAccess. -The framework must be extended in order to create record instances. -The minimum that an extenson must provide is a top level PVStructure and a process method -but the framework provides for complex extensions.
- -EPICS version 4 is a set of related products in the EPICS
-V4 control system programming environment:
-relatedDocumentsV4.html
-
This is the 27-Nov-2012 version of the definition of pvDatabaseCPP. -This is the original version. -
-This is the beginning of the implementation of pvDataBaseCPP. -It describes the features that will be provided. -The class definitions for PVRecord and PVDatabase are defined but not implemented.
- - -This document descibes a C++ implementation of some of the components in pvIOCJava. -It extracts the core components required to create a network accessible database of smart -memory resident records. -pvDatabaseCPP does not and will not implement any of the specialized support that pvIOCJava -provides. Instead other projects will implement the specialized support. -It is expected that many services will be created that do not require the full features provided -by pvIOCJava. In the future pvIOCJava should be split into multiple projects with one of -them named pvDatabaseJava. -
- -A brief description of a pvDatase is that it is a network accessible set of smart memory resident -records. Each record has data composed of a top level PVStructure. Each record has a name which is -the channelName for pvAccess. A local Channel Provider implements the complete ChannelProvider and -Channel interfaces as defined by pvAccess. -This local provider is accessed by the remote pvAccess server. -A record is smart because code can be attached to a record.
-This document describes components that provides the following features: -
database does not itself implement pvRecord instances. -Instead it provides a base classes that make it easy to create record instances. -What does have to be implemented is a top -level PVStructure and the following two methods:
-Directory example/record has an example PVRecord implementation. -It implements a counter. -The top level structure is:
--structure - long value --
NOTE: The example compiles but does not build because nothing -is implemented.
- -This is the class description. -The example extends PVRecord.
-
-class ExampleRecord :
- public virtual PVRecord
-{
-public:
- POINTER_DEFINITIONS(ExampleRecord);
- static PVRecordPtr create(epics::pvData::String const & recordName);
- virtual ~ExampleRecord();
- virtual bool isSynchronous();
- virtual void process(
- epics::pvDatabase::RecordProcessRequesterPtr const &processRequester);
-private:
- ExampleRecord(epics::pvData::String const & recordName,
- epics::pvData::PVStructurePtr const & pvStructure,
- epics::pvData::PVLongPtr const &pvValue);
- epics::pvData::PVLongPtr pvValue;
-};
-
-where
-This is the class implementation.
-
-ExampleRecord::~ExampleRecord(){}
-
-PVRecordPtr ExampleRecord::create(String const & recordName)
-{
- String properties;
- PVStructurePtr pvStructure = getStandardPVField()->scalar(pvLong,properties);
- PVLongPtr pvValue = pvStructure->getLongField("value");
- PVRecordPtr pvRecord(new ExampleRecord(recordName,pvStructure,pvValue));
- return pvRecord;
-}
-
-ExampleRecord::ExampleRecord(
- String const & recordName,
- PVStructurePtr const & pvStructure,
- PVLongPtr const &pvValue)
-: PVRecord(recordName,pvStructure),
- pvValue(pvValue)
-{}
-
-bool ExampleRecord::isSynchronous() {return true;}
-
-void ExampleRecord::process(
- RecordProcessRequesterPtr const &processRequester)
-{
- pvValue->put(pvValue->get() + 1);
- processRequester->recordProcessResult(Status::Ok);
- processRequester->recordProcessComplete();
-}
-
-where
-This is a main for creating and running the example.
-
-int main(int argc,char *argv[])
-{
- String recordName("exampleRecord");
- PVRecordPtr pvRecord = ExampleRecord::create(recordName);
- PVDatabasePtr pvDatabase = PVDatabase::getMaster();
- pvDatabase->addRecord(pvRecord);
- cout << recordName << "\n";
- string str;
- while(true) {
- cout << "Type exit to stop: \n";
- getline(cin,str);
- if(str.compare("exit")==0) break;
-
- }
- return 0;
-}
-
-The main program creates an example record and adds it to the database. -It then runs until the process is stopped by typing exit. -
Until the process is stopped, -pvAccess clients can put and get the value field. -For example
--pvget exampleRecord -pvput exampleRecord 5 --
Will both work.
-This documentation describes the first phase of a phased implementation of pvDatabaseCPP: -
Future phases of pvDatabaseCPP should include:
-The completion of each phase provides useful features that can be used without waiting for the -completion of later phases. -The rest of this document discusses only the first phase.
-The first phase will only implement record processing, i. e. -the process method has to do everything itself without any generic field support. -This will be sufficient for starting to implement services. -The following are the minimium features required
-The following sections provide a first attempt to describe the classes required for the first -phase.
-The last section gives a brief overview of the features provided by pvIOCJava.
- -The classes in pvDatabase.h implement a database of memory resident -smart records. The next subsection has the definitions for all the classes -defined in this header file. -It describes the following classes:
-Each class is described in a separate subsection.
- -
-class PVRecord
-{
-public:
- POINTER_DEFINITIONS(PVRecord);
- PVRecord(
- epics::pvData::String const & recordName,
- epics::pvData::PVStructurePtr const & pvStructure);
- virtual ~PVRecord();
- virtual void process(
- RecordProcessRequesterPtr const &recordProcessRequester) = 0;
- virtual bool isSynchronous() = 0;
- epics::pvData::String getRecordName();
- PVRecordStructurePtr getPVRecordStructure();
- PVRecordFieldPtr findPVRecordField(
- epics::pvData::PVFieldPtr const & pvField);
- void lock();
- void unlock();
- void registerClient(PVRecordClientPtr const & pvRecordClient);
- void unregisterClient(PVRecordClientPtr const & pvRecordClient);
- void detachClients();
- void beginGroupPut();
- void endGroupPut();
- void registerListener(PVListenerPtr const & pvListener);
- void unregisterListener(PVListenerPtr const & pvListener);
- void removeEveryListener();
- epics::pvData::Status processRequest();
- void queueProcessRequest(
- RecordProcessRequesterPtr const &recordProcessRequester);
- void addRequester(epics::pvData::RequesterPtr const & requester);
- void removeRequester(epics::pvData::RequesterPtr const & requester);
- void message(
- epics::pvData::String const & message,
- epics::pvData::MessageType messageType);
- epics::pvData::String toString();
- epics::pvData::String toString(int indentLevel);
-};
-
-The methods are: -
-class PVRecordField {
-public:
- POINTER_DEFINITIONS(PVRecordField);
- PVRecordField(
- epics::pvData::PVFieldPtr const & pvField,
- PVRecordPtr const & pvRecord);
- virtual ~PVRecordField();
- PVRecordStructurePtr getParent();
- epics::pvData::PVFieldPtr getPVField();
- epics::pvData::String getFullFieldName();
- epics::pvData::String getFullName();
- PVRecordPtr getPVRecord();
- bool addListener(PVListenerPtr const & pvListener);
- void removeListener(PVListenerPtr const & pvListener);
- void postPut();
- virtual void message(
- epics::pvData::String const & message,
- epics::pvData::MessageType messageType);
-};
-
-When PVRecord is created it creates a PVRecordField for every field in the PVStructure -that holds the data. It has the following methods: -
- -
-class PVRecordStructure : public PVRecordField {
-public:
- POINTER_DEFINITIONS(PVRecordStructure);
- PVRecordStructure(
- epics::pvData::PVStructurePtr const & pvStructure,
- PVRecordFieldPtrArrayPtr const & pvRecordField);
- virtual ~PVRecordStructure();
- PVRecordFieldPtrArrayPtr getPVRecordFields();
- epics::pvData::PVStructurePtr getPVStructure();
- virtual void message(
- epics::pvData::String const & message,
- epics::pvData::MessageType messageType);
-};
-
-When PVRecord is created it creates a PVRecordStructure for every structure field in the PVStructure -that holds the data. It has the following methods: -
-
-class PVListener {
-public:
- POINTER_DEFINITIONS(PVListener);
- virtual ~PVListener();
- virtual void dataPut(PVRecordFieldPtr const & pvRecordField) = 0;
- virtual void dataPut(
- PVRecordStructurePtr const &
- requested,PVRecordFieldPtr const & pvRecordField) = 0;
- virtual void beginGroupPut(PVRecordPtr const & pvRecord) = 0;
- virtual void endGroupPut(PVRecordPtr const & pvRecord) = 0;
- virtual void unlisten(PVRecordPtr const & pvRecord) = 0;
-};
-
-where
-
-class RecordProcessRequester :
- virtual public epics::pvData::Requester
-{
-public:
- POINTER_DEFINITIONS(RecordProcessRequester);
- virtual ~RecordProcessRequester();
- virtual void becomeProcessor() = 0;
- virtual void recordProcessResult(epics::pvData::Status status) = 0;
- virtual void recordProcessComplete() = 0;
-};
-
-where
-
-class PVRecordClient {
- POINTER_DEFINITIONS(PVRecordClient);
- virtual ~PVRecordClient();
- virtual void detach(PVRecordPtr const & pvRecord);
-};
-
-where
-
-class PVDatabase : virtual public epics::pvData::Requester {
-public:
- POINTER_DEFINITIONS(PVDatabase);
- static PVDatabasePtr getMaster();
- virtual ~PVDatabase();
- PVRecordPtr findRecord(epics::pvData::String const& recordName);
- bool addRecord(PVRecordPtr const & record);
- bool removeRecord(PVRecordPtr const & record);
-private:
- PVDatabase();
-};
-
-where
-Not yet described.
-A brief description is that it must implement the following components of pvIOCJava:
-The following are the direct sub packages of pvIOCJava/src/org/epics/pvioc:
-In addition there is one class file JavaIOC.java. -This is starting a IOC instance. -This is not required for pvIOCCPP which is either a main or runs as part of a V3 IOC.
- -