I agree - I'd see if a few yields (Sleep(0)) in the worker thread
alleviate things.
Lowering the priority runs the risk of the worker taking an eternity to
complete.
--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--
"Paul G. Tobey [eMVP]" <p space tobey no spam AT no instrument no spam
DOT com> wrote in message So, you want to prioritize that below the rest of the UI. That's fine,
but you should understand that the priority means that, as long as the
UI is doing *anything*, your background thread will get *zero* time
(not just a small amount of time, not almost no time, absolutely no
time). You certainly don't want to set its priority to lowest, or I
wouldn't want to set its priority to lowest, at least. If the UI is
waiting, at any time, for something from the background thread to be
complete, it will almost certainly wait forever. You might try setting
it just below the priority of the UI thread, or you might alter the
code, leaving the priority at the default, so that it periodically goes
to sleep for a little while.
Paul T.
message Well, the background sync doesn't completely lock the UI, it just
makes it a lot slower. It does quite a lot. It does some local
database calls, does some webservice calls and if there's new data, it
loops through all the records and saves them to the local database.
This is quite an intensive process. However, when checking for updates
and there's nothing new, the background sync takes about 20 seconds.
Posting the complete code of what the sync does goes too far. Here's
my code to start the thread:
private static void StartBackgroundThread()
{
Thread backgroundSyncThread = new Thread(DoBackgroundSync);
backgroundSyncThread.Priority = ThreadPriority.Lowest;
backgroundSyncThread.IsBackground = true;
backgroundSyncThread.Start();
}
And here's the DoBackgroundSync method:
private static void DoBackgroundSync()
{
_backgroundThreadRunning = true;
// Wait a while so that the automatic backgroundsync won't
interfere with the startup of the application
Thread.Sleep(60000);
// While the EnableBackgroundSync property is set to true continue
to sync
while (_enableBackgroundSync)
{
if (!BackgroundSyncRunning & !_syncRunning)
{
if (!_connectionManager.IsConnected)
{
try
{
_connectionManager.CheckConnection();
}
catch (Exception ex)
{
TextLogger.Log(TextLogger.LogLevelType.Error, "SyncManager
BackgroundSync Connection error: {0}", ex.ToString());
}
}
if (_connectionManager.IsConnected &&
!AppSettings.InitializeApplication) // don't perform a backgroundsync
while initializing the app
{
_backgroundSyncRunning = true;
// First, stop automatic dispatching
if (!AppSettings.WorkOffline && _requestManager.Running)
StopAutomaticDispatch();
try
{
StartSync(null);
}
catch(Exception ex)
{
TextLogger.Log(TextLogger.LogLevelType.Error, "Error during
Background Sync: {0}", ex.ToString());
}
while (BackgroundSyncRunning)
{
// Wait for backgroundsync to finish
}
// When finished with Sync, restart automatic dispatching
if (!AppSettings.WorkOffline && !_requestManager.Running)
StartAutomaticDispatch();
}
}
if (_enableBackgroundSync)
{
TextLogger.Log(TextLogger.LogLevelType.Info, "SyncManager
BackgroundSync: sleeping for {0} minutes", AppSettings.SyncInterval);
// Put the thread to sleep for the interval
Thread.Sleep(AppSettings.SyncInterval*60*1000);
}
}
_backgroundThreadRunning = false;
}
The call to StartSync(null) does all the hard work
.
--
Jeffry van de Vuurst
CWR Mobility
www.cwrmobility.com
--
If it's on a background thread it's going to compete for resources
just like anything running, but it should never cause the UI to lock
unless it's using 100% of the CPU, and in that case it's poorly
designed and would cause the problem no matter where you put it.
Running it at a lower priority would allow the UI to get quantum
before the background worker, but it wouldn't fit the flaw in what
the thread is doing, or help your battery life.
You've got something wrong in how you're either creating and using
the thread, or in what it's doing. We'd need to see code to tell you
more.
--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--
in message Hi Chris,
Thanks for your reply. I guess my question was not clear enough.
It's not the GC that causes the non-responsiveness. My assumption is
that the non-responsiveness is caused by running my background sync
on a thread with the same priority as the main thread. So when the
background sync starts, both the UI and the sync are competing for
the CPU cycles, right?
That's the reason I started creating my own thread and setting the
priority lower than the main thread. However, the blog post from
Daniel Moth gives me some concerns because it discourages changing
the priority of a thread because of unexpected behavior (mentioning
the garbage collection). At least, that is my understanding of the
article.
So maybe my question should be: is it ok to have a background thread
running on a lower priority so not to interfere with the GUI, or
does running on lower priority have unexpected side effects (like
mentioned in the article) and should be avoided?
Thanks,
--
Jeffry van de Vuurst
CWR Mobility
www.cwrmobility.com
--
If a GC occurs, all threads in the process are suspended. Doesn't
matter what priority any of the threads are.
Are you sure it is a GC that's causing the non-responsiveness?
--
Chris Tacke
OpenNETCF Consulting
Managed Code in the Embedded World
www.opennetcf.com
--
in message Hi,
I have a CF 2.0 app that uses 2 background threads. 1 for polling
for a network connection and 1 for performing a background sync.
First I used the OpenNETCF BackgroundWorker for this purpose.
However, when performing a background sync the UI became
unresponsive. Now I changed it to a regular thead using:
Thread backgroundSyncThread = new Thread(DoBackgroundSync);
backgroundSyncThread.Priority = ThreadPriority.Lowest;
backgroundSyncThread.IsBackground = true;
backgroundSyncThread.Start();
However, I read here
http://www.danielmoth.com/Blog/2004/08/threads-and-threadpriority-with-net.html,
that chaging the priority of threads may be risky because garbage
collection could run on the low priority thread.
It's an article from August 2004 but does mention CF 2.0 beta 1.
Does this still apply? And if so, what are other ways to make sure
that the (potentially long) running background thread doesn't
freeze the UI? Is doing a Thread.Sleep(0) from the worker thread
effective? I've read different stories about the effectiveness of
Thread.Sleep(0)...
Thanks,
