Multiple threads destroying performance

I have an application which performs it's own graphical rendering, i.e. I completely bypass Swing/AWT and go fullscreen and just render straight to a BufferStrategy's graphics. This works fine and the render loop is in it's own thread and merrily churns away giving quite acceptable performance. However, what baffles me is that if I create just one more thread, the performance of the thread chokes. The new thread has a run() consists of just a while(true) loop that does nothing. My question is why would this second thread cause such a hit in performance?
I'll grant the render thread has to load images and what not, but it was instantaneous before the second thread and now takes 30secs to load. Both threads are the same priority but even if I tank the priority of the second thread to low I still get the same 30 sec delay. Any ideas? If it'll help I can post the code but my main render thread needs quite a lot of support code so I'm not sure if it'd help that much and the second thread is just as I said, an empty while(true) loop.
Thanks in advance.

Ok, I've decided I will try the sleep(x) where x != 0
and see the results. But I think I may also just
restructure my code to see if I can do an on-demand
thread instead. Not sure if it'll work for my
purposes but I'll see. The only thing is this thread
is used for playing a sound file, so I'll have to
somehow work it so that sounds don't start piling up
on each other.I've seen Swing apps do pretty impressive multimedia stunts, very smoothly -- well, after long startup anyways. So, unless you want to go through it as an exercise, I'd think using event dispatcher should work fine.
>
The only thing I'm really curious about is why does
changing the thread priority to LOW not make a
difference. Is it not possible to change time slice
allocation that way?I've never had much success with fiddling around thread priorities. But I've never cared enough to look very closely. As I recall, JVM 1.4.1 (since 1.3?) uses native thread handler to improve performance -- look in the docs to confirm. And I don't think Windoze let you adjust thread priority, except the two broad categories: foreground/background.
But the above passage is mostly based on my guesses and memories, and I've been willfully oblivious to Windoze. So don't sue me. ;>
Cheers,
Bo

Similar Messages

Can multiple threads write to the database?

I am a little confused from the statement in the documentation: "Berkeley DB Data Store does not support locking, and hence does not guarantee correct behavior if more than one thread of control is updating the database at a time."
1. Can multiple threads write to the "Simple Data Store"?
2. Considering the sample code below which writes to the DB using 5 threads - is there a possibility of data loss?
3. If the code will cause data loss, will adding DB_INIT_LOCK and/or DB_INIT_TXN in DBENV->open make any difference?
#include "stdafx.h"
#include <stdio.h>
#include <windows.h>
#include <db.h>
static DB *db = NULL;
static DB_ENV *dbEnv = NULL;
DWORD WINAPI th_write(LPVOID lpParam)
DBT key, data;
char key_buff[32], data_buff[32];
DWORD i;
printf("thread(%s) - start\n", lpParam);
for (i = 0; i < 200; ++i)
memset(&key, 0, sizeof(key));
memset(&data, 0, sizeof(data));
sprintf(key_buff, "K:%s", lpParam);
sprintf(data_buff, "D:%s:%8d", lpParam, i);
key.data = key_buff;
key.size = strlen(key_buff);
data.data = data_buff;
data.size = strlen(data_buff);
db->put(db, NULL, &key, &data, 0);
Sleep(5);
printf("thread(%s) - End\n", lpParam);
return 0;
int main()
db_env_create(&dbEnv, 0);
dbEnv->open(dbEnv, NULL, DB_CREATE | DB_INIT_MPOOL | DB_THREAD, 0);
db_create(&db, dbEnv, 0);
db->open(db, NULL, "test.db", NULL, DB_BTREE, DB_CREATE, 0);
CreateThread(NULL, 0, th_write, "A", 0, 0);
CreateThread(NULL, 0, th_write, "B", 0, 0);
CreateThread(NULL, 0, th_write, "B", 0, 0);
CreateThread(NULL, 0, th_write, "C", 0, 0);
th_write("C");
Sleep(2000);
}

Here some clarification about BDB Lock and Multi threads behavior
Question 1. Can multiple threads write to the "Simple Data Store"?
Answer 1.
Please Refer to http://docs.oracle.com/cd/E17076_02/html/programmer_reference/intro_products.html
A Data Store (DS) set up
(so not using an environment or using one, but without any of the DB_INIT_LOCK, DB_INIT_TXN, DB_INIT_LOG environment regions related flags specified
each corresponding to the appropriate subsystem, locking, transaction, logging)
will not guard against data corruption due to accessing the same database page and overwriting the same records, corrupting the internal structure of the database etc.
(note that in the case of the Btree, Hash and Recno access methods we lock at the database page level, only for the Queue access method we lock at record level)
So,
if You want to have multiple threads in the application writing concurrently or in parallel to the same database You need to use locking (and properly handle any potential deadlocks),
otherwise You risk corrupting the data itself or the database (its internal structure).
Of course , If You serialize at the application level the access to the database, so that no more one threads writes to the database at a time, there will be no need for locking.
But obviously this is likely not the behavior You want.
Hence, You need to use either a CDS (Concurrent Data Store) or TDS (Transactional Data Store) set up.
See the table comparing the various set ups, here: http://docs.oracle.com/cd/E17076_02/html/programmer_reference/intro_products.html
Berkeley DB Data Store
The Berkeley DB Data Store product is an embeddable, high-performance data store. This product supports multiple concurrent threads of control, including multiple processes and multiple threads of control within a process. However, Berkeley DB Data Store does not support locking, and hence does not guarantee correct behavior if more than one thread of control is updating the database at a time. The Berkeley DB Data Store is intended for use in read-only applications or applications which can guarantee no more than one thread of control updates the database at a time.
Berkeley DB Concurrent Data Store
The Berkeley DB Concurrent Data Store product adds multiple-reader, single writer capabilities to the Berkeley DB Data Store product. This product provides built-in concurrency and locking feature. Berkeley DB Concurrent Data Store is intended for applications that need support for concurrent updates to a database that is largely used for reading.
Berkeley DB Transactional Data Store
The Berkeley DB Transactional Data Store product adds support for transactions and database recovery. Berkeley DB Transactional Data Store is intended for applications that require industrial-strength database services, including excellent performance under high-concurrency workloads of read and write operations, the ability to commit or roll back multiple changes to the database at a single instant, and the guarantee that in the event of a catastrophic system or hardware failure, all committed database changes are preserved.
So, clearly DS is not a solution for this case, where multiple threads need to write simultaneously to the database.
CDS (Concurrent Data Store) provides locking features, but only for multiple-reader/single-writer scenarios. You use CDS when you specify the DB_INIT_CDB flag when opening the BDB environment: http://docs.oracle.com/cd/E17076_02/html/api_reference/C/envopen.html#envopen_DB_INIT_CDB
TDS (Transactional Data Store) provides locking features, adds complete ACID support for transactions and offers recoverability guarantees. You use TDS when you specify the DB_INIT_TXN and DB_INIT_LOG flags when opening the environment. To have locking support, you would need to also specify the DB_INIT_LOCK flag.
Now, since the requirement is to have multiple writers (multi-threaded writes to the database),
then TDS would be the way to go (CDS is useful only in single-writer scenarios, when there are no needs for recoverability).
To Summarize
The best way to have an understanding of what set up is needed, it is to answer the following questions:
- What is the data access scenario? Is it multiple writer threads? Will the writers access the database simultaneously?
- Are recoverability/data durability, atomicity of operations and data isolation important for the application? http://docs.oracle.com/cd/E17076_02/html/programmer_reference/transapp_why.html
If the answers are yes, then TDS should be used, and the environment should be opened like this:
dbEnv->open(dbEnv, ENV_HOME, DB_CREATE | DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_TXN | DB_INIT_LOG | DB_RECOVER | DB_THREAD, 0);
(where ENV_HOME is the filesystem directory where the BDB environment will be created)
Question 2. Considering the sample code below which writes to the DB using 5 threads - is there a possibility of data loss?
Answer 2.
Definitely yes, You can see data loss and/or data corruption.
You can check the behavior of your testcase in the following way
1. Run your testcase
2.After the program exits
run db_verify to verify the database (db_verify -o test.db).
You will likely see db_verify complaining, unless the thread scheduler on Windows weirdly starts each thread one after the other,
IOW no two or ore threads write to the database at the same time -- kind of serializing the writes
Question 3. If the code will cause data loss, will adding DB_INIT_LOCK and/or DB_INIT_TXN in DBENV->open make any difference?
Answer 3.
In Your case the TDS should be used, and the environment should be opened like this:
dbEnv->open(dbEnv, ENV_HOME, DB_CREATE | DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_TXN | DB_INIT_LOG | DB_RECOVER | DB_THREAD, 0);
(where ENV_HOME is the filesystem directory where the BDB environment will be created)
doing this You have proper deadlock handling in place and proper transaction usage
so
You are protected against potential data corruption/data loss.
see http://docs.oracle.com/cd/E17076_02/html/gsg_txn/C/BerkeleyDB-Core-C-Txn.pdf
Multi-threaded and Multi-process Applications
DB is designed to support multi-threaded and multi-process applications, but their usage
means you must pay careful attention to issues of concurrency. Transactions help your
application's concurrency by providing various levels of isolation for your threads of control. In
addition, DB provides mechanisms that allow you to detect and respond to deadlocks.
Isolation means that database modifications made by one transaction will not normally be
seen by readers from another transaction until the first commits its changes. Different threads
use different transaction handles, so this mechanism is normally used to provide isolation
between database operations performed by different threads.
Note that DB supports different isolation levels. For example, you can configure your
application to see uncommitted reads, which means that one transaction can see data that
has been modified but not yet committed by another transaction. Doing this might mean
your transaction reads data "dirtied" by another transaction, but which subsequently might
change before that other transaction commits its changes. On the other hand, lowering your
isolation requirements means that your application can experience improved throughput due
to reduced lock contention.
For more information on concurrency, on managing isolation levels, and on deadlock
detection, see Concurrency (page 32).

Help with running multiple threads

I'm new to programming with threads. I want to know how to run
multiple threads at the same time. Particularly for making games
in Java which I'm also begining to learn. For running multiple
threads at the same time, do you have to put two run() methods
in the source? If not then how do you make two threads or more
run at the same time?
Thanks for helping.

For running multiple
threads at the same time, do you have to put two run()
methods
in the source? Hi there,
Each thread is presumably performing a task. You may be performing the same task multiple times or be performing different tasks at once. Either way, each task would typically be contained within the run() method of a class. This class would either be a subclass of java.lang.Thread (extends Thread) or would be an implementation of java.lang.Runnable (implements Runnable). In either case, you would define a method with signature (public void run()...). The difference comes into play when you wish to actually perform one of these tasks. With a subclass of Thread, you would simply perform:
new MyTask().start();
With an implementation of Runnable, you would do this:
new Thread(new MyTask()).start();
This assumes you don't need to monitor the threads, won't be sending any messages to your tasks or any such thing. If that were the case, you would need to tuck away those returns to new MyTask() for later access.
In order to launch two threads simultaneously, you would have something along the lines of:
new MyTask().start();
new MyOtherTask().start();
Now it is perfectly possible that MyTask() would complete before MyOtherTask() managed to start in which case it wouldn't appear as if you had actually had multiple threads running, but for non-trivial tasks, the two will likely overlap. And of course, in a game, these tasks would likely be launched in response to user input, which means that you wouldn't have any control over when or in what order they executed.
Anyhow, it's as simple as that. You should also consider following the Java Threading trail which shows a simple example of using multiple threads. You can find it at:
http://java.sun.com/docs/books/tutorial/essential/threads/index.html
Regards,
Lynn

Breaking a Program Execution into Multiple Threads

Hi,
We want to run a BAPI with Differenet parameters synchronoulsy in the same program as the BAPI is taking a very lon time for execution.
We are Planning to break up the execution and the call o the BAPI into multiple threads that can run synchronously. How can this concept implemented in SAP ABAP.
Thanks in advance.
Arunava

I am using parallel processing in my current client. Basis define a dialog processes group that we can use. This way our program will be limited to the number of processing give in the group. For example, our production system has 5 servers and each servers has 15 dialog processes. Basis reserve in the group 5 dialog processes for each group. So when we run our program, we are limited to 25 processes. We use function module SPT_INITIALIZE to find out the number of dialog processes and free processes for our group.
The logic of the program as follow:
Do loop
Call function module with starting new task and destination in group performing end of task subroutine
Enddo
Wait until all task completed (check help on wait-you need to keep track of the number of record completed)
In end of task subroutine, use command receive results from function to get the return parameters.
Hope this helps.
Cheers

Spawning multiple threads ?

Hi,
          In our application, the content of the main page is being
          retrieved from different databases. All the requests originiate from
          one JSP to different databases to retrieve the info. As the JSP
          processes each of the request sequentailly, there is considerable delay
          before the contents are displayed to the user.
          What I want to acheive is spawn multiple threads and display the content
          to the user in fractions as each thread returns. For eaxmple, if the
          user has subscribed to three news servers.. I want to be able to
          display the news from first server to the user without waiting to
          recieve response from the other two servers.
          What is the best approach to follow for such requirements ?? Any
          thoughts on this would be highly appreciated.
          Thanks,
          Sam


I think you may need to spawn it into HTML frame. Each frame will perform
          and download independently.
          Is it what you need ?
          Siros
          "sam ernie" <[email protected]> wrote in message
          news:[email protected]..
          > Hi,
          >
          > In our application, the content of the main page is being
          > retrieved from different databases. All the requests originiate from
          > one JSP to different databases to retrieve the info. As the JSP
          > processes each of the request sequentailly, there is considerable delay
          > before the contents are displayed to the user.
          >
          > What I want to acheive is spawn multiple threads and display the content
          > to the user in fractions as each thread returns. For eaxmple, if the
          > user has subscribed to three news servers.. I want to be able to
          > display the news from first server to the user without waiting to
          > recieve response from the other two servers.
          >
          > What is the best approach to follow for such requirements ?? Any
          > thoughts on this would be highly appreciated.
          >
          > Thanks,
          >
          > Sam
          >

Managing Multiple threads accessing a single instance of a class

Hi,
i have to redesign a class, say X, in such a way that i manage multiple threads accessing a single instance of the class, we cannot create multiple instances of X. The class looks like this:
Class X{
boolean isACalled=false;
boolean isInitCalled=false;
boolean isBCalled=false;
A(){
isACalled=true;
Init(){
if(!isACalled)
A();
B();
C();
isInitCalled=true;
B(){
if(!isACalled)
A();
isBCalled=true;
C(){
if(!isACalled)
A();
if(!isBCalled)
B();
}//end of class
Init is the method that would be invoked on the single instance of this class.
Now i cannot keep the flags as instance variables coz different threads would have differrent status of these flags at the same time, hence i can make them local, but if i make them local to one method, the others won't be able to check their status, so the only solution i can think of is to place all the flags in a hashtable local to method INIT AND INITIALIZE ALL OF them to false, as init would call other methods, it would pass the hashtable reference as an additional parameter, the methods would set the flags in the hashtable and it would be reflectecd in the original hashtable, and so all the methods can have access to the hashtable of flags and can perform their respective checks and setting of flags.
This all would be local to one thread, so there's no question of flags of one thread mixin with the flags of some other thread.
My question is :
Is this the best way, would this work?
In java, everything is pass by value, but if i pass the hashtable reference, would the changes made inside the called method to the hashtable key-value would be visible in the original hashtable declared inside the calling method of which the hashtable is local variable?

In Java object variables are passed "by copy of reference", and primitive variables "by value".
The solution with HashMap/Hashtable you suggest is ok, but I think you should read about ThreadLocal class:
http://java.sun.com/j2se/1.4.2/docs/api/java/lang/ThreadLocal.html

Multiple Threads Using System.out.println...

i have a client server app and each client that connects to the server has its own thread.
i am running the server on a pc using windows xp and to run it i just use a bat file which uses cmd.exe and my output using System.out.println prints out in the cmd.exe.
each of my threads is using System.out.println to send debug info and outs quite often.
after the screen fills a scroll bar appears at the right and you can scroll back to see past output.
my app is all running ok but when i had a ton of output coming in all at once i tried to scroll back to see the older output and realized that if i click down on the scroll bar and fight the new input it freezes my server app. then when i release it it continues lol.
it made me wonder if output from multiple threads when there are many all at once (say 20 or 30 threads all outputing at the exact same time) could cause a slow down or effect the performance of the server?
i use a debug variable so i can just turn this output 100 % off except for critical errors so there would be no output but i am just curious as to whether or not it may be causing problems when its on.

That's not a performance issue, I guess System.out.println() simply gets blocked by the console while you're scrolling and thus your app stalls, until you stop doing that.
Maybe you should look into logging.

Servlet spawning multiple threads causes server to freeze PC

I'm attempting to write a servlet which, upon receipt of a particular GET request, spawns a thread to do various work which can then be queried by a different GET request. A third type of GET request stops a specified thread.
This is working fine, except that I can only seem to have spawned one thread at a time. When I spawn another thread, my entire PC stops responding (even Windows Task Manager becomes so sluggish that I cannot kill the server) , and I have to do a hard reset of my PC. I'm using Sun Java System Application Server. The server logs do not contain any errors. I've tried the NetBeans debugger a bit, and it seems to happen when I call the start() method of the Thread.
This is my first experience with servlets, as well as my first experience with Sun Java System Application Server. I'm also not a Java expert by any means. I'm sure I'm doing something stupid, but I haven't a clue what.
I can post my code if necessary, but does anyone have any idea what could be causing the server to stop responding just because a servlet spawns two threads? Should I post my code?
Sorry if this is a n00b question. Thanks in advance.

I think you may need to spawn it into HTML frame. Each frame will perform
          and download independently.
          Is it what you need ?
          Siros
          "sam ernie" <[email protected]> wrote in message
          news:[email protected]..
          > Hi,
          >
          > In our application, the content of the main page is being
          > retrieved from different databases. All the requests originiate from
          > one JSP to different databases to retrieve the info. As the JSP
          > processes each of the request sequentailly, there is considerable delay
          > before the contents are displayed to the user.
          >
          > What I want to acheive is spawn multiple threads and display the content
          > to the user in fractions as each thread returns. For eaxmple, if the
          > user has subscribed to three news servers.. I want to be able to
          > display the news from first server to the user without waiting to
          > recieve response from the other two servers.
          >
          > What is the best approach to follow for such requirements ?? Any
          > thoughts on this would be highly appreciated.
          >
          > Thanks,
          >
          > Sam
          >

How to protect the creation of a db across multiple threads/processes?

Given a multi-process, multi-threaded application, and one database file to be created, how can I guarantee that only one of the threads in one of the processes successfully creates the database, when ALL of the threads are going to either attempt to create it, or open it (if it already exists) upon startup?
My current logic for all threads is:
set open flags to DB_THREAD
start transaction
attempt to open the db
if ENOENT
abort transaction
change open flags to DB_CREATE | DB_EXCL | DB_THREAD
retry
else if EEXIST
abort transaction
change open flags to DB_THREAD
retry
else if !ok
# some other error
end
commit transaction
I'm testing on Linux right now, with plans to move to Windows, AIX, and Solaris. What I'm experiencing on Linux is several of the threads (out of 10 threads I'm testing) will succeed in creating the database. The others will receive either either succeed in opening the first time through, or will receive the EEXIST when they do the open w/ create flags - ultimately, they open the same created db (I'm presuming the last one that's created by one of the other threads). Effectively, the open with DB_CREATE | DB_EXCL is not ensuring that only one DB is created. I was under the impression that opening in a transaction would guarantee this, but it does not, or maybe I'm doing something incorrectly?
Should DB_CREATE | DB_EXCL and opening in a transaction guarantee that only one thread can create the database? Do I need to use another synchronization method?
Note: I am running off of a local disk, not over NFS or anything like that.
I tried taking out my transaction and using DB_AUTO_COMMIT instead, still no go - multiple threads still report they successfully created the DB. Using BDB 4.5.
Thanks,
Kevin Burge

Brian,
Thanks for the reply. I think I'm doing what you said, unless I'm misunderstanding. I do have all threads try to do the DB_CREATE | DB_EXCL. Are you saying I shouldn't use the DB_EXCL flag?
The problem I was seeing with 10 threads calling open w/ DB_CREATE | DB_EXCL on the same db:
* Between 1 and 9 threads would return success from db->open with the creation flags.... but the last one to create "wins".
* All the other threads would get EEXIST, as expected.
The threads that "lost", do get a successful return code from "open" with the create flags, but all data written to them is lost. They act normally except for the fact that the have a deleted file-handle that they are writing to. There's no indicator that records written to them are going into the void.
My test:
I had 10 threads each trying to create or open a recno db, then append 10 records, for a total of 100 records expected. Ultimately, I would end up with between 20 to 100 records in the db, depending on how many of the threads said they successfully created the db. So, if 5 threads said they created the db successfully, then 40 records would be missing, because 4 of those threads were writing to deleted file handles. If 2 threads said they created the db, then 10 records would be missing....If 8 threads, then 70 records missing, etc.
In other words, multiple threads creating the db appears to work correctly, because there are no errors. It was the missing records that caught my attention, and prompted my question on this forum.
For what it's worth, I've worked around the problem by opening a similarly named file via the open() system call, with O_CREAT|O_EXCL, which is guaranteed to be atomic. The first thread that can create this temp file is the only thread that can actually create the db - all others sleep upon open with ENOENT until it's created.
Thanks,
Kevin

Multiple Thread of a xml publisher report - messed up fonts in the PDF out

We are running 60000 invoices at a given time. In order to get the job done faster, the xml publisher report is set up to run mulitple threads. Each thread running unique set of invoices.
I am seeing this issue, randomly.
The pdf output of the invoice is having the fonts messed up. font 10 shows up as 14 and the invoice looks very bad.
When i rerun the same set of invoices it looks absolutely normal.
Also if I retrieve the xml output of the bad pdf and view it through the xmlpub desktop, it looks perfectly fine.
Two times we saw this issue
PRODUCTION
- when i run 8 threads, i saw this issue in one of the thread and affected one invoice. (Production- 1 concurrent processing node+ 5 OPP processes and 5 threads + MEMORY is J:oracle.apps.fnd.cp.gsf.GSMServiceController:-mx3072m )
TEST INSTANCE
- when i ran with 16 threads, one of the thread running xml pub report affected all the invoices (UAT environment-1 concurrent processing node+ 7 OPP processes and 1 threads + MEMORY is J:oracle.apps.fnd.cp.gsf.GSMServiceController:-mx3072m )
Looks like it is happening when running multiple threads.
The formatting command or information is getting lost somewhere and the report is all messed up.
Please advise.
Thanks
SJ

Really appreciate your response. Can you pls give little more details.
1] Are there any standard API's which I can use to submit XML publisher report from the JSP pages
2]Is there any sample code snippet for any of the options that I can refer to..or pls let me know the API's, I will check on them
Appreciate any help

PrinterException when multiple threads try to print report using JRC

Iam using Crystal Report's JRC for printing reports, it works fine.
But the problem araises when i use multiple threads.
I used the following:
reportClientDocument.getPrinterOutputController().printReport(.....); to print.
I get the following exception
Caused by: java.awt.print.PrinterException: No printer named "\\ch03\printer05" could be found.
Without multiple thread it works fine.
I have been scratching my head for days on this problem, any help is very much appreciated..

If an API doesn't specifically say that it is thread safe then it isn't likely to be thread safe and the only way to approach it is to assume that it isn't.

How do i use multiple threads( very much real time), using JavaFX?

I'm creating an application, using JavaFX because one can create awesome GUI using JavaFX. I need to know how to create real time multiple threads using javafx.
JavaFX doesn't support creation of multiple threads, but i think there is another way of doing it. I need it work in real time as my application works with an hardware (wacom intous 3 tablet), and i need mutiple threads to get all the parameters from the stylus of the tablet simultaneously...
any code which will help me out or explaination on how to go about this is appreciated...
Help required quickly...

See example at
[http://jfxstudio.wordpress.com/2009/06/09/asynchronous-operations-in-javafx/|http://jfxstudio.wordpress.com/2009/06/09/asynchronous-operations-in-javafx/]

Problem with multiple threads accessing the same Image

I'm trying to draw into one Image from multiple threads. It works fine for a while, but then suddenly, the image stops updating. Threads are still running but the image won't update. I'm using doublebuffering and threads are simply drawing counters into Image with different speed.
It seems like the Image gets deadlocked or something. Anyone have any idea what's behind this behavior or perhaps better solution to do such thing.
Any help will be appreciated.

Sorry Kglad, I didn't mean to be rude. With "No coding
errors" I meant the animation itself runs with no errors. I'm sure
you could run the 20 instances with no freezing (that's why I put
the post :) ) But I'm affraid it is an animation for a client, so I
cannot distribute the code.
Perhaps I didnt explain the situation clearly enough (in part
because of my poor english...).-
- By 20 instances I mean 20 separated embedded objects in the
html
- The animation is relatively simple. A turned on candle, in
each cycle I calculate the next position of the flame (that
oscilates from left to right). The flame is composed by 4
concentric gradients. There is NO loops, only an 'onEnterFrame'
function refreshing the flame each time.
- It's true that I got plenty variables at the _root level.
If that could be the problem, how can I workaround it?
- It is my first time trying to embed so many objects at the
same time too. No idea if the problem could be the way I embed the
object from the html :(
- The only thing I can guess is that when a cycle of one of
the object is running, the other 19 objects must wait their turn.
That would explain why the more instances I run, the worst results
I get. In that case, I wonder if there's a way to run them in a
kind of asynchronous mode, just guessing...
Any other comment would be appreciated. Anyway, thanks a lot
everybody for your colaboration.

How to use multiple threads and swing for displaying status/interaction

I have a Swing-app which have to show progress and allow userinteraction for these tasks:
* First:
retrieve a list of IDs(String) from the database (single thread running)
* Second:
some work on the id-list and list written to hd (same thread as above)
* Third:
retrieve Objects (based on the id-list) from different sources (Multiple Threads are running)
To show the status I have a JProgressBar (indeterminate while task1&2 running) and
a JTextArea showing the current status (connect,retrieve list, sort, ...)
When task3 is starting the JTextArea have to disappear and be replaced by a ScrollPane
with an array of Labels/TextAreas showing the status of each thread.
While theses threads are working, the ID-list will be consumed and the JProgressBar
shows the remaining precentage of the hole progress.
Everything is working so far (excepts UI :) , the problem(s) I have:
I need the threads to interacts with the user through the ui. e.g: "Connection to db-xyz lost! reconnect?"
But I don´t know how to do this correctly.
I think one way would be to send an event to the ui... but how?
(the ui must know which thread is calling to unpause it after user answered)
I know that threads should NOT change the swing(-container) - How do I notify the ui that a thread has a question?
Since these threads are really time-consuming the UI is not updated frequently,
how can I increase this? (perhaps using another thread-priority?)
thanks for help!

if/when your threads need to interact with the UI, they can create a Runnable & send it to SwingUtilities.invokeLater or invokeAndWait. This Runnable can popup a message to the user, and act on the choice of the user (reconnect, cancel, ...). This action could be something which "unpauses" the task thread.
You may need to do synchronisation between the code in the Runnable & the Thread to which it is related - so the latter Thread knows when the user has made the choice.

Suddenly, I've been put on multiple threads over multiple firefox problems, which is filling up my inbox. How do I get out of these?

Details? I posted a question about one problem (for which no answers have been offered, but that's okay) and somehow, I've become part of multiple threads about various firefox problems. I have no interest in any of these questions/problems.
How do I get out of these threads? I get about 15-20 emails a day! Firefox is by far the worst community I've even been dragged into....

Sorry you are having problems.
Have a look at your settings in the dropdown from the username or https://support.mozilla.org/en-US/users/settings
Not too sure what you could subscribe to accidentally that causes that behaviour though.
It would be interesting to know what option caused all the email. If something has gone wrong and you are getting e-mails that you should not be getting we can refer this to the admins to look into. The Firefox sumo community certainly does not intentionally spam, and if you are having a problem lets find out more, because others may have a problem and not have reported it.

Multiple threads destroying performance

Similar Messages

Maybe you are looking for