Multi-threaded undercutting of dual locks in TestSTand 3.0

Group,
    I have a test sequence that is running 16 threads to test radios. About midway into my testing one of the threads will some how take priority and will not wait for another thread to finish its testing. The first time a thread executes a series of tests all is fine. But when the second or later thread attempts to run the same code it is always stops waiting for the thread that is one dual lock ahead of it. Let me setup the condition. Assume Thread 1 is just finished with Lock Audio and Thread 2 begins executing Lock Audio. At some point in the middle of the dual locks sequence, Thread 1 takes priority and begins running its test leaving Thread 2 having not finished its set of tests within the dual locks. In fact, thread 2 is unable to do anything until thread one has gone completely through its entire sequence file. How can one thread countermand the previous thread. Example of testing below:
Lock Audio
Lock PortAA
   Take a measurement
UnLock PortAA
Lock PortAA
   Take a measurement
UnLock PortAA
UnLock Audio
Lock VolumeMax
Lock PortAA
   Take a measurement
UnLock PortAA
Lock PortAA
    Take a measurement
Unlock PortAA
UnLock VolumeMax
..........etc..............

Did you mean to have an unlock audio in the middle? It seems odd that Port AA is sometimes used under the audio lock and sometimes not. It makes me think you might not really be locking/unlocking the locks that you intended to.

Similar Messages

Multi Threading..on object locking

when a synchronised method of an object is invoked by a thread that object gets locked. can another thread invoke unsynchronized method of the same object? howz it possible..if it is possible..pl give the rationale behind this..

Yes it can. And the reason is part of your homework assignment.

"Inconsistent cursor cache. Out of range cursor" error on dual processor multi thread

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
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error might be cause by a collision of threads accessing the
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is so because the error keeps coming from a statement accessing
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Our only solution now is to put Mutex on Statements accessing
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from 8.1.6 to 8.1.7. The wierd thing on this is that the system
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Middleware. Hope you can give me any insights on this problem.

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

"SQL-02103: Inconsistent cursor cache." error on a dual processor multi threaded apps

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

"SQL-02103 Inconsistent cursor cache." error on dual processor multi threaded system

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

"SQL-02103: Inconsistent cursor cache." error on dual processor multi thread apps

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

I have a C++ with Pro*C++ COM object running on a Win2000 OS on
a dual processor Middleware. The program is being called by a
service in a multi threaded way. An oracle error like ORA-2103
and SQL-02103 will be generated after running the program. We've
tried putting mutex on every SQL statement in Pro*C and it works
but the systems became very very slow. We concluded that the
error might be cause by a collision of threads accessing the
same Table or different tables having foreign constraints. This
is so because the error keeps coming from a statement accessing
Table A and following errors comes from a Table B having a
foreign key on Table A.
Our only solution now is to put Mutex on Statements accessing
same tables or tables with foreign constraints but this will
make our system run very very slow. I dont know if the problem
is in our Oracle Database because we already upgraded our system
from 8.1.6 to 8.1.7. The wierd thing on this is that the system
is running smoothly without oracle errors on a SINGLE PROCESSOR
Middleware. Hope you can give me any insights on this problem.

VI calling from a multi-thread Teststand

Hello,
My test system tests four UUTs at the same time(with batch mode in TS), the code is based on LabVIEW and call from TS, so every step the same VI will be accessed by four thread. however, it runs quite slow even i set the reentrant execution in VI propertise.
My Quesition:
Can I do it like this in multi-thread mode of TS?
How can I make it fast? (convert VI to dll?????)
Any help will be appreciated.
Thanks,Steven

Hello Allen,
Thanks for your help.
Problem: I have a LabVIEW VI with parallel code blocks. These blocks run in parallel as expected when I run my VI directly or from a top level VI. However, the code blocks seem to run sequentially when I call my VI from TestStand. Why is this happening and how can I fix it?
Solution: In order to fix this behavior, simply set the VI Properties of "Execution" of your LabVIEW VI to "Other 1" or "Other 2". This change will make the parallel code blocks in your LabVIEW VI run in parallel as expected. To change this setting, from your LabVIEW VI, go to File»VI Properties. Select the Execution category. Change the Preferred Execution System to be either other 1 or other 2.
You need to make this change to any LabVIEW VI with parallel code blocks that is called from TestStand. The reason for this is that TestStand is using the LabVIEW ActiveX interface to run LabVIEW VIs. The LabVIEW ActiveX interface sets the caller's execution system to "User Interface" by default. This execution system is not recommended for a VI with parallel code blocks. If your LabVIEW VI's execution system is set to "Same as caller" (which is the default setting when creating a new LabVIEW VI), then it is executed in the User Interface thread when run through the LabVIEW ActiveX interface. This prevents the blocks to be executed in parallel.
In fact, only one block in my LabVIEW code, but it accessed by four thread from TS. I am sure that my VI can be accessed by four thread simultaneously if I enable the reentrant excution in VI property. I also have tried what mentioned in above document but no use.
However, if i only add a 1000ms delay to my LabView code instead of the 'calculation', it is fast enough! what is happening or something i set wrong?
I don't want to convert all my LabView code to DLL cos too many VIs here, and difficult for mantenance either.
Any other good solution???
Thank you Allen...
Steven

What's wrong with my multi-threaded Matrix Mult. code? 1 thread is fastest

For some reason, 1 thread performs the best. What's wrong with my implementation?
import java.util.Random;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class Matrix {
 private int values[][];
 private int rows;
 private int columns;
 public Matrix(int r, int c) {
 this.rows = r;
 this.columns = c;
 this.values = new int[r][c];
 private void randomize() {
 Random generator = new Random();
 for (int r = 0; r < this.rows; r++) {
 for (int c = 0; c < this.columns; c++) {
 this.values[r][c] = generator.nextInt(10);
 public String toString() {
 String out = "";
 for (int r = 0; r < this.rows; r++) {
 for (int c = 0; c < this.columns; c++) {
 if (c == 0) out += "[";
 else out += "\t";
 out += this.values[r][c];
 out += "]\n";
 return out;
 public boolean equals(Object obj) {
 Matrix other = (Matrix) obj;
 if (this.columns != other.columns || this.rows != other.rows) {
 return false;
 for (int r = 0; r < this.rows; r++) {
 for (int c = 0; c < this.columns; c++) {
 if (this.values[r][c] != other.values[r][c]) {
 return false;
 return true;
 // matrix multiplication using single thread
 public Matrix times(Matrix other) {
 assert(this.columns == other.rows);
 Matrix out = new Matrix(this.rows, other.columns);
 for (int r = 0; r < this.rows; r++) {
 for (int c = 0; c < other.columns; c++) {
 int dotProduct = 0;
 for (int z = 0; z < this.columns; z++) {
 dotProduct += this.values[r][z] * other.values[z][c];
 out.values[r][c] = dotProduct;
 return out;
 // matrix multiplication with many threads
 public Matrix ptimes(Matrix other, int numberOfThreads) throws InterruptedException { // parallel
 assert(this.columns == other.rows);
 Matrix out = new Matrix(this.rows, other.columns);
 ExecutorService threadExecutor = Executors.newFixedThreadPool(numberOfThreads);
 for (int r = 0; r < this.rows; r++) {
 for (int c = 0; c < other.columns; c++) {
 threadExecutor.execute(new HelperThread(r, c, this, other, out));
 threadExecutor.shutdown();
 threadExecutor.awaitTermination(2, TimeUnit.DAYS);
 return out;
 private class HelperThread implements Runnable {
 private int row;
 private int col;
 private Matrix a;
 private Matrix b;
 private Matrix out;
 HelperThread(int r, int c, Matrix a, Matrix b, Matrix o) {
 this.row = r;
 this.col = c;
 this.a = a;
 this.b = b;
 this.out = o;
 public void run() {
 int dotProduct = 0;
 for (int z = 0; z < a.columns; z++) {
 dotProduct += this.a.values[row][z] * this.b.values[z][col];
 this.out.values[row][col] = dotProduct;
 public static void main(String[] args) throws InterruptedException {
 int size = 100;
 Matrix a = new Matrix(size, size);
 a.randomize();
 Matrix b = new Matrix(size, size);
 b.randomize();
 for (int t = 1; t < 15; t++) {
 long start = new Date().getTime();
 System.out.print(t + " threads: ");
 Matrix c = a.ptimes(b, t);
 //System.out.println(c);
 long finish = new Date().getTime();
 System.out.println((finish - start) + " milliseconds");
 Matrix d = a.times(b);
 assert(c.equals(d));
}

This one is even faster. On my dual core I get:
Warmup
Single Threaded
5.20616 milliseconds
5.52872 milliseconds
5.12708 milliseconds
5.59048 milliseconds
5.16104 milliseconds
5.1838 milliseconds
5.37104 milliseconds
5.1788 milliseconds
5.18636 milliseconds
5.15736 milliseconds
Multi Threaded with 2 threads
3.22184 milliseconds
2.86552 milliseconds
2.86284 milliseconds
3.67032 milliseconds
3.08032 milliseconds
2.97388 milliseconds
2.93084 milliseconds
3.44012 milliseconds
2.89744 milliseconds
2.88136 milliseconds
As you can see the Multi-Threaded versions are now faster.
 // matrix multiplication with many threads
 ExecutorService threadExecutor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
 public Matrix ptimes(Matrix other) throws InterruptedException, ExecutionException {
 assert (this.columns == other.rows);
 Matrix out = new Matrix(this.rows, other.columns);
 Future futures[] = new Future[rows];
 for (int r = 0; r < this.rows; r++) {
 futures[r] = threadExecutor.submit(new HelperThread(r, this, other, out));
 for(Future f : futures) {
 f.get();
 return out;
 private class HelperThread implements Callable<Object> {
 private int row;
 private Matrix a;
 private Matrix b;
 private Matrix out;
 HelperThread(int r, Matrix a, Matrix b, Matrix o) {
 this.row = r;
 this.a = a;
 this.b = b;
 this.out = o;
 public String call() throws Exception {
 int dotProduct = 0;
 for (int c = 0; c < b.columns; c++) {
 for (int z = 0; z < a.columns; z++) {
 dotProduct += this.a.values[row][z] * this.b.values[z][c];
 this.out.values[row][c] = dotProduct;
 return null;
 public static void main(String[] args) throws InterruptedException, ExecutionException {
 int size = 100;
 Matrix a = new Matrix(size, size);
 a.randomize();
 Matrix b = new Matrix(size, size);
 b.randomize();
 System.out.println("Warmup");
 for (int t = 0; t < 1000; t++) {
 Matrix c = a.ptimes(b);
 Matrix d = a.times(b);
 assert (c.equals(d));
 System.out.println("Single Threaded");
 for (int t = 0; t < 10; t++) {
 long start = System.nanoTime();
 Matrix d = a.times(b);
 long finish = System.nanoTime();
 System.out.println((finish - start)/1000000.0 + " milliseconds");
 System.out.println("Multi Threaded with " + Runtime.getRuntime().availableProcessors() + " threads");
 for (int t = 0; t < 10; t++) {
 long start = System.nanoTime();
 Matrix c = a.ptimes(b);
 long finish = System.nanoTime();
 System.out.println((finish - start)/1000000.0 + " milliseconds");
 Matrix d = a.times(b);
 assert (c.equals(d));
 System.exit(0);
 }

Multi-Thread application and common data

I try to make a multi-Thread application. All the Threads will update some common data.
How could I access the variable �VALUE� with the Thread in the following code:
public class Demo {
private static long VALUE;
public Demo(long SvId) {
VALUE = 0;
public static class makeThread extends Thread {
public void run() {
VALUE++;
public static long getVALUE() {
return VALUE;
The goal is to get the �VALUE� updated by the Thread with �getVALUE()�
Thanks for your reply
Benoit

That code is so wrong in so many ways......
I know you're just experimenting here, learning what can and can't be done with Threads, but bad habits start early, and get harder to kick as time goes on. I am going to give a little explanation here about what's wrong, and what's right.. If you're going to do anything serious though, please, read some books, and don't pick up bad habits.
Alright, The "answer" code. You don't use Thread.sleep() to wait for Threads to finish. That's just silly, use the join() method. It blocks until the threads execution is done. So if you have a whole bunch of threads in an array, and you want to start them up, and then do something once they finish. Do this.
for(int k=0; k<threads.length; k++) {
threads[k].start();
for(int k=0; k<threads.length; k++) {
threads[k].join();
System.out.println("All Threads Done");Now that's the simple problem. No tears there.
On to the java memory model. Here where the eye water starts flowing. The program you have written is not guarenteed to do what you expect it to do, that is, increment VALUE some amount of time and then print it out. The program is not "Thread Safe".
Problem 1) - Atomic Operations and Synchronization
Incrementing a 'long' is not an atomic operation via the JVM spec, icrementing an int is, so if you change the type of VALUE to an int you don't have to worry about corruption here. If a long is required, or any method with more then one operation that must complete without another thread entering. Then you must learn how to use the synchronized keyword.
Problem 2) - Visiblity
To get at this problem you have to understand low level computing terms. The variable VALUE will NOT be written out to main memory every time you increment it. It will be stored in the CPUs cache. If you have more then one CPU, and different CPUs get those threads you are starting up, one CPU won't know what the other is doing. You get memory overwrites, and nothing you expect. If you solve problem 1 by using a synchronized block, you also solve problem 2, because updating a variable under a lock will cause full visiblity of the change. However, there is another keyword in java.. "volatile".. A field modified with this keyword will always have it's changes visible.
This is a very short explaination, barely scratching the surface. I won't even go into performance issues here. If you want to know more. Here's the resources.
Doug Lea's book
http://java.sun.com/docs/books/cp/
Doug Lea's Site
http://g.cs.oswego.edu
-Spinoza

InfoPath: the multi-threading challenge

Or to be more specific: calling a DataSource from a different thread.
A project I'm working on includes an InfoPath form in which some heavy duty tasks are executed. These tasks can take over 10+ seconds to execute. To avoid the GUI to get stuck during execution, multi-threading is implemented. The problem lies in providing
feedback to the user. Several methods have been used, but all end in the exceptions shown below.
Unlike WinForms and such, InfoPath does not seem to provide a way to invoke the GUI. What we are trying to do is change field values to reflect the status of the process. This is done through the MainDataSource. I've tried several methods to call
this datasource through another thread, like invoking a provided delegate, or execution context. However all these methods have similar results.
When calling a method or property on the datasource the following exception is thrown:
System.InvalidOperationException was unhandled
Message="Operation is not valid due to the current state of the object."
Source="Microsoft.Office.InfoPath.Client.Internal.Host"
StackTrace:
       at Microsoft.Office.Interop.InfoPath.SemiTrust.ICLRExtensionsWrapper.IncrementSqmPoint(Int32 idDataPt)
       at Microsoft.Office.InfoPath.Internal.DataSourceHost.CreateNavigator()
       at Form1.FormCode.ContextCallbackMethod(Object obj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 74
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 68
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
This seems to indicate the DataSource is locked for some reason. Even the ReadOnly property can not be read.
When calling the SetValue method on an XPathNavigator provided by a datasource and passed through another thread, the following exception is thrown:
System.AccessViolationException was unhandled
Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
Source="Microsoft.Office.InfoPath.Client.Internal.Host.Interop"
StackTrace:
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.NativeHelpers.SetText(IXMLDOMNode* , Char* )
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.MsxmlNodeImpl.set_Text(String strText)
       at Microsoft.Office.InfoPath.MsxmlNavigator.SetValue(String value)
       at Form1.FormCode.DelegateMethod(XPathNavigator nav) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 81
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 70
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
I have searched through the internet but am unable to find any useful information about this subject. There are only a few weeks remaining before the deadline. A work-around has been implemented, but since it requires additional active user interaction
it is far from ideal. I hope you can help me in finding a solution.

For anyone who is still interested all this time later....
I wouldn't use a Dispatcher in InfoPath simply because InfoPath requires .Net 2.0 only and Dispatcher was not added until .Net 3.0 which means you would have to enforce installation of .Net 3.0 yourself.
There is an easy alternative which is SynchronizationContext (more specifically a WindowsFormsSynchronizationContext).
Also I suggest you do not use ThreadStart but rather use one of the more modern and well known threading paradigms. A good alternative is a BackgroundWorker.
e.g.
private BackgroundWorker _Worker;
public void InternalStartup()
InitializeWorker();
((ButtonEvent)EventManager.ControlEvents["Button"]).Clicked += new ClickedEventHandler(ButtonClick);
public void InitializeWorker()
_Worker = new BackgroundWorker();
_Worker.WorkerReportsProgress = true;
_Rorker.WorkerSupportsCancellation = true;
_Worker.DoWork += new DoWorkEventHandler(_Worker_DoWork);
_Worker.ProgressChanged += new ProgressChangedEventHandler(_Worker_ProgressChanged);
_Worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_Worker_RunWorkerCompleted);
public void ButtonClick(object sender, ClickedEventArgs e)
if (_Worker.IsBusy)
_Worker.CancelAsync();
else
// Very important to include this line!
AsyncOperationManager.SynchronizationContext = new WindowsFormsSynchronizationContext();
_Worker.RunWorkerAsync();
void _Worker_DoWork(object sender, DoWorkEventArgs e)
// Do stuff in another thread and report back to the UI thread.
object state;
int percentage = 0;
_Worker.ReportProgress(percentage, state).
public void _Worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
// This is called on the thread that started the worker.
// In this case the UI thread which means it is safe to use the MainDataSource.
CreateNavigator().SelectSingleNode("my:Main/my:Progress", NamespaceManager).SetValue(e.ProgressPercentage);
void _Worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
// Do anything you want to do on completion here.
One thing of note is that the SynchronizationContext in InfoPath for some reason or other always seems to be Null. The result is that when you call RunWorkerAsync() it captures the current synchronization context (null) which means the default is used and
a ProgressChanged is called on a new thread each time. To prevent this we need to manually set the context before calling RunWorkerAsync() which is done using the AsyncOperationManager.

Using multi threading to access 2 RS232 ports

Hi,
I'm a beginner in multi threading, so this question may be a very basic one....
I'm Using TS3.5 + CVI 8.01 to communicate withs 2 RS232 ports. I thought to use mult threading so I can process 2 steps in parallel rather than in series.
This is what I do:
1) I defined 2 subsequences, each of them call the same CVI function. I use the sub sequence parameters to transfer the com number.
2) My CVI application includes one dll for this specific project and another one, a general dll to handle RS232 functions. The RS232 dll uses one global buffer than collects all the traffic on the com.
QUESTIONS:
1) What happens when 2 seperate threads run the same function in the RS232 dll? (in terms of memory etc...). Does each one use a different buffer (in terms of memory allocation), or, both of them writes to the same buffer? Obviously, if they writes to the same buffer, then, my function will not operate properly.
2) What happens in TestStand after the 2 steps in new threads have finished their execution? does the next step run back in the same threads the sequence run before?
Thanks
Rafi

Rafi,
Glad to hear you were able to make some ground on your application. As for all of your questions, I'll try to answer as many as I can.
First, when you are talking about your global buffer, is it created in TestStand or in the DLL itself? When you use DLLs, global variables or global structures are shared between all threads that call your DLL. On the other hand, if your buffer is declared inside of the DLL it is global for the DLL but not shared and would be a separate buffer for each call.
With your run-time error in TS, it would definitely be helpful to have more information about the error. From what you explained (executing fine on the first call, but failing on future executions), it sounds like the resource is not being released after the first execution.
As far as a specific example for TestStand Multithreading, you'll want to look at the TestStand Development Library and, specifically, Multithreading in TestStand. If you look and browse through the Application Notes and Tutorials section, as well as the Technical Presentations section, you will learn a great deal about multithreading and what options you have in TestStand. For a specific example, you may want to look at This Example. You could also look in the <TestStand>\Examples (where <TestStand> is the directory where TS is installed) at the MultiUUT example for an example of multithreading in TS. These examples may not be exactly what you need, but they should give you a jump start.
As far as making your DLL multithread safe, it is definitely not necessary; however, there are some significant advantages described in this article: Designing Thread-Safe DLLs. It is an MSDN article that focuses on Visual Basic, but it has some helpful information that can apply to C as well.
Hopefully this can help you move further. I have attached a list of links at the end of this post with other helpful links for you as well. Keep us posted with your progress.
Matt Mueller
NI
Links:
General Information on Multithreading for C Programmers
Building Multithreading Applications with LabWindows/CVI
Multithreading in LabWindows/CVI
Easy Multithreading Programming in LabWindows/CVI
Multithreading for Rookies

Analysis for Office support multi thread?

Does Analysis for Office support multi thread/core? If so, what verison? I tried searching around this site as well as note 1466118 - Hardware & Software requirements for Analysis, edition for MS Office but was unable to find an answer.
I am on an Intel dual cpu with hyper threading turned on so it essentially looks like 4 cores. When I execute an Analysis View, I rarely see the EXCEL.EXE process go above 25% CPU utilization. I have plenty of RAM and hard drive space.
64bit Windows 7
32bit Office 2010
AAO 1.3.5.2288
Thanks

I found the following info at:
Excel 2010 Performance: Performance and Limit Improvements
Large Data Sets and 64-bit Excel
The 64-bit version of Excel 2010 is not constrained to 2 GB of RAM like 32-bit applications. Therefore, 64-bit Excel 2010 enables users to create much larger workbooks. 64-bit Windows enables a larger addressable memory capacity, and 64-bit Excel is designed to take advantage of that capacity. For example, users are able to fill more of the grid with data than was possible in previous versions of Excel. As more RAM is added to the computer, Excel uses that additional memory, allows larger and larger workbooks, and scales with the amount of RAM available.
In addition, because 64-bit Excel enables larger data sets, both 32-bit and 64-bit Excel 2010 introduce improvements to common large data set tasks such as entering and filling down data, sorting, filtering, and copying and pasting data. Memory usage is also optimized to be more efficient, in both the 32-bit and 64-bit versions of Excel.
Multi-Core Processing
Additional investments were made to take advantage of multi-core processors and increase performance for routine tasks. Starting in Excel 2010, the following features use multi-core processors: saving a file, opening a file, refreshing a PivotTable (for external data sources, except OLAP and SharePoint), sorting a cell table, sorting a PivotTable, and auto-sizing a column.
For operations that involve reading and loading or writing data, such as opening a file, saving a file or refreshing data, splitting the operation into two processes increases performance speed. The first process gets the data, and the second process loads the data into the appropriate structure in memory or writes the data to a file. In this way, as soon as the first process beings reading a portion of data, the second process can immediately start loading or writing that data, while the first process continues to read the next portion of data. Previously, the first process had to finish reading all the data in a certain section before the second process could load that section of the data into memory or write the data to a file.

Is ABAP multi-threading safe?

When implementing the Singleton design pattern in Java, we must use keyword synchronized with getInstance() method to ensure multi-threading safety, so that we can get the one and only instance.
What shall I do in ABAP? or just leave it alone? Would you help me find a example?
thanks and regards,
Davin,WANG

Hi Davin,
I do not understand fully what you are going to do in ABAP terms so I hope my comment will be of any value.
Multithreading may be achieved in ABAB by calling a function with the addition STARTING NEW TASK IN GROUP.... See my sample program for <a href="https://wiki.sdn.sap.com/wiki/display/Snippets/Easilyimplementparallelprocessinginonlineandbatchprocessing">Easily implement parallel processing in online and batch processing</a>
The second question may be solved by help of SAP lock concept. This is used primarily to secure a consistent database by not allowing two processes to change data at the same time. Chose a lock object of your choice and set at start of first instance. At end, remove the lock. Before creating the second instance, try so set the same lock. If you get a foreign lock error, you know the process is running.
See documentation on lock objects on how to lock/unlock.
Regards,
Clemens
Hope your internet connection is broken no longer so you can read this.

Aggregate Storage And Multi-Threading/Multi-Core Systems

Please pardon if this question has been asked before, but the Forum search is not returning any relevant results.
We are in the process of purchasing hardware for an 11.1.2 Essbase environment. We are going 64-bit, on Windows 2008, with either 32 GB or 64 GB of system RAM. The debate we are having is the number of CPUs and cores per CPU. We have not built any ASO databases as of yet, but we plan to launch a major BSO to ASO conversion project once 11.1.2 is off the ground here.
Historically, with BSO, we did not see performance improvements significant enough to justify the cost of additional CPUs when we ran calcs on multi-CPU systems vs. single or dual CPU systems, even when the settings and design should have taken the most advantage of BSO's multi-threading capabilities. However, it would seem that ASO's design may be able to make better use of multi-core systems.
I know that there are a lot of factors behind any system's performance, but in general, is ASO in 11.1.2 written well enough to make it worthwhile to consider, say, a four CPU, total 16 core system vs. a 2 CPU, total four core system?

Grand central dispatch - infancy, not really doing its job, and I don't think apps have to be specifically written for HT, but they do have to not do things that they use to - prevent threads from going to sleep! or be parked.
high usage is not necessarily high efficiency. often the opposite.
Windows 7 seems to be optimized for multi-core thanks to a lot of reworking. Intel wants and knows it isn't possible to hand code, that the hardware has to be smarter, too. But the OS has a job, and right now I don't think it does it properly. Or handle memory.
Gulftown's 12MB cache will help, and over all should be 20% more efficient doing its work.
With dual processors, and it doesn't look like there are two quick path bridges, data shuffling has led to memory thrashing. Use to be page thrashing with not enough memory. Then core thrashing but having the cores, but not integrated (2008 is often touted as being greatest design so far, but it was FOUR dual-cores, 2009 was the first with a processor that really was new design and (native) 4-core.
One core should be owned by the OS so it is always available for its own work and housekeeping.
The iTunes audio bug last year showed how damaging and not to implement code and how a thread could usurp processing and add a high cpu temperature while basically doing nothing, sort of a denial of service attack on the processor - those 80*C temps people had.
All those new technology features under development and not like OpenCL, GCD and even OpenGL are tested, mature but rather 1.0 foundation for the future. A year ahead of readiness.

What is multi threading?

Hi all,
What is multi threading? How to implement multi threading in ABAP?
Regards,
Bryan

Hi
How the vision connector framework works
The connector interacts with an SAP application using connector modules. The connector modules make calls to SAP's Native Interfaces and pass data (business object or event data) to and from an SAP application. The connector's flexible design enables different modules to be used for different tasks such as initializing the connector with the SAP application or passing business object data.
Communication between the connector and an SAP application
The connector uses SAP's Remote Function Call (RFC) library to communicate with an SAP application. SAP's RFC API allows external programs to call ABAP function modules within an SAP application.
Processing business objects
The connector is metadata driven. Metadata, in the WebSphere business integration system, is application-specific data that is stored in business objects and that assists a connector module in its interaction with the application. A metadata-driven connector module handles each business object that it supports based on metadata encoded in the business object definition rather than on instructions hard-coded in the connector module.
Business object metadata includes the structure of a business object, the settings of its attribute properties, and the content of its application-specific information. Because connector modules are metadata driven, they can handle new or modified business objects without requiring modifications to the connector-module code.
The vision connector framework uses the value of the verb application-specific information in the top-level business object to call the appropriate connector module to process the business object. The verb application-specific information provides the classname of the connector module.
The verb application-specific information of most top-level business objects must identify the classname of the connector module. The syntax of this verb application-specific information is:
AppSpecificInfo = PartialPackageName.ClassName,
For example,
AppSpecificInfo = sap.sapextensionmodule.VSapBOHandler,
In this example, sap.sapextensionmodule is the partial package name, and VSapBOHandler is the classname. The full package name includes the com.crossworlds.connectors prefix, which the WebSphere business integration system adds to the name automatically. In other words, the full text of the example is:
com.crossworlds.connectors.sap.sapextensionmodule.VSapBOHandler
Note:
The verb application-specific information of most top-level business objects must use a comma (,) delimiter after the connector classname. However, the Server verb, which is used by the RFC Server Module, is delimited instead by a semi-colon (;). For information about the Server verb, see How the RFC Server Module works and Supported verbs.
You need not specify the package name and classname for the verb application-specific information if the business object is used:
by the ALE Module to process application events; however, when you use the ALE Module to process service call requests, you must specify the package name and classname
by the ABAP Extension Module, which uses the default business object handler (sap.sapextensionmodule.VSapBOHandler)
Important:
Customer-generated connector modules that process business objects for the RFC Server Module must specify a full package name, which must begin with bapi. For example, bapi.client.Bapi_customer_getdetail2. The full package name in this example is bapi.client, and the classname is Bapi_customer_getdetail2.
Most business object processing is specific to each connector module. By default the connector uses the ABAP Extension Module. For more information on business object processing for the ABAP Extension Module, see Installing and customizing the ABAP Extension Module and Business object data routing to ABAP handlers. .
For more information on specifying verb application-specific information for the ALE Module, see Event processing and Processing multiple IDocs with a wrapper business object.
Processing multiple concurrent interactions
The Adapter Framework can create separate threads for processing an application event and a business object request. When processing multiple requests from the integration broker, it can create multiple threads to handle multiple business object requests. For example, when InterChange Server is the integration broker, the connector can receive multiple business object requests from multiple collaborations or from a multi-threaded collaboration.
Figure 4 illustrates the multi-threading architecture.
Figure 4. Multi-Threading Architecture of the Connector for SAP
Event processing
The connector performs the following steps when handling a poll call:
The Adapter Framework creates a single dedicated thread to handle poll calls. This thread calls the pollForEvents() method of the vision connector framework at the frequency specified in the PollFrequency configuration property.
The thread polls SAP, which uses a dialog process to locate and return the event.
Note:
If the connector's MaxNumberOfConnections configuration property evaluates to a number greater than 1, the vision connector framework dedicates a connection to SAP for polling. If MaxNumberOfConnections evaluates to 1, event and service-call request processing share a single connection to SAP.
The polling thread dies only when the connector shuts down.
Note:
Because the RFC Server connector agent pushes events out of SAP instead of polling for events, it spawns its own threads instead of using threads created by the connector framework. Because the ALE connector agent uses the RFC Server connector agent to access events, it also spawns its own threads instead of using threads created by the connector framework when it processes events.
Request processing
Independently of polling, the Adapter Framework can create multiple request-processing threads, one for each request business object. Each request thread instantiates the appropriate business object handler.
For example, when processing business object requests from InterChange Server, the number and type of business object handlers depends on the number and type of the collaborations sending the requests:
If multiple collaborations send business objects, each request thread instantiates a business object handler of the appropriate type.
If a multi-threaded collaboration sends multiple business objects of the same type, the request threads instantiate an equal number of business object handlers of that type.
If the connector's MaxNumberOfConnections configuration property evaluates to a number greater than 1, the vision connector framework dedicates one connection to SAP for polling and allocates the remaining connections to a pool used only for request processing.
As illustrated in Figure 4, the connector performs the following steps when handling a business object request:
The Adapter Framework creates a separate thread for each business object request. Each thread calls the doVerbFor() method of the Vision business object handler.
If the connector's MaxNumberOfConnections configuration property evaluates to a number greater than 1, the Vision business object handler checks the vision connector framework's connection pool to determine if a connection handle is available.
If the handle is available, the thread sends the request to SAP, which uses a dialog process to handle the request.
If the handle is not available, the thread waits until one becomes available. Thread sequencing determines the order in which each business object handler thread claims or waits for an available connection handle.
If the connector's MaxNumberOfConnections configuration property evaluates to 1, the Vision business object handler shares a connection with event processing.
SAP releases the dialog process after it completes processing and sends a return code.
The connector releases the connection handle after it receives the return code from SAP.
Setting the number of available connections
Use the MaxNumberOfConnections configuration property to specify the maximum number of connection handles available. The number of connections cannot exceed the number of dialog processes.
SAP locks the dialog process while processing an interaction, releasing it only when the interaction completes. Therefore, multiple concurrent requests lock an equal number of dialog processes until processing finishes.
Important:
Before setting a value for MaxNumberOfConnections, contact your SAP BASIS administrator to determine an appropriate value to maximize throughput without negatively affecting performance on the application server.
Support for multiple connections
By default the connector supports multiple-threads.

REWARD IF USEFULL

Multi-threaded undercutting of dual locks in TestSTand 3.0

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