Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: VNC: list

Screen updates go slow after 2 weeks

 

 

VNC list RSS feed   Index | Next | Previous | View Threaded


stevelpub at gmail

Feb 12, 2009, 5:42 AM

Post #1 of 3 (1207 views)
Permalink
Screen updates go slow after 2 weeks

Hi all,

I'm running VNC server 4.1.2 on a win2k server and have found that screen
updates start to happen very slowly after having the server up for around 2
weeks. I'm making fairly heavy use of VNC (I'm connected to the server for
at least 4hrs per day). Any suggestions on how I can troubleshoot this?
Some observations so far....

- Its not a gradual performance degradation - the server goes straight from
working fine to taking around 5-20s to update the screen - it's like
something breaks.
- This has happened 3 times so far and the system seems to fail after
(roughly) the same period of time.
- The delay only seems to occur on certain events...moving the mouse,
dragging windows, updating of counters/graphs within windows seems OK.
Changing the window focus (e.g. alt-tab) is a problem.
- Some of the time, the window gets partially drawn (usually the border and
toolbars), then it freezes and the rest gets drawn (equally quickly) after
the freeze.
- Not everything gets delayed - if I have Windows Task Manager set to
'always on top' with the performance graphs showing & I change the window
focus from one application to another, I see the borders of the new
application get drawn, the window then sits there for around 10s and the
rest of the detail then gets filled in. Meanwhile, the task manager graphs
have continued to scroll/update throughout.
- The system remains 99% idle throughout the freeze. I don't see the CPU
utilization go up and the winvnc4.exe process doesn't appear to grab any
more cycles.
- Pings from the client to the server remain at 1-2ms throughout the freeze.
- The slow response remains regardless of which client machine or VNC client
I connect from (i've tried realvnc and tightvnc clients on windows and linux
hosts).
- Restarting the VNC server process on the server doesn't help.
- Raising the priority of the VNC server process doesn't help.
- So far, rebooting the Win2k server is the only way I've been able to fix
the problem.

Cheers,

Steve.
_______________________________________________
VNC-List mailing list
VNC-List [at] realvnc
To remove yourself from the list visit:
http://www.realvnc.com/mailman/listinfo/vnc-list


jnw at realvnc

Feb 16, 2009, 6:39 AM

Post #2 of 3 (1103 views)
Permalink
RE: Screen updates go slow after 2 weeks [In reply to]

Steve,

Have you checked the memory usage of the server when it gets into this state?
It's also worth checking the Windows event logs to see if there are any
tell-tale errors from core OS components or drivers around the time the
problem occurs. Finally, you can also check the number of handles that
processes are holding via the Task Manager, which may help you determine
whether it's a resource issue.

Regards,

--
Wez @ RealVNC Ltd


> -----Original Message-----
> From: vnc-list-admin [at] realvnc [mailto:vnc-list-admin [at] realvnc] On
> Behalf Of steve l
> Sent: 12 February 2009 13:42
> To: vnc-list [at] realvnc
> Subject: Screen updates go slow after 2 weeks
>
> Hi all,
>
> I'm running VNC server 4.1.2 on a win2k server and have found that
> screen
> updates start to happen very slowly after having the server up for
> around 2
> weeks. I'm making fairly heavy use of VNC (I'm connected to the server
> for
> at least 4hrs per day). Any suggestions on how I can troubleshoot
> this?
> Some observations so far....
>
> - Its not a gradual performance degradation - the server goes straight
> from
> working fine to taking around 5-20s to update the screen - it's like
> something breaks.
> - This has happened 3 times so far and the system seems to fail after
> (roughly) the same period of time.
> - The delay only seems to occur on certain events...moving the mouse,
> dragging windows, updating of counters/graphs within windows seems OK.
> Changing the window focus (e.g. alt-tab) is a problem.
> - Some of the time, the window gets partially drawn (usually the border
> and
> toolbars), then it freezes and the rest gets drawn (equally quickly)
> after
> the freeze.
> - Not everything gets delayed - if I have Windows Task Manager set to
> 'always on top' with the performance graphs showing & I change the
> window
> focus from one application to another, I see the borders of the new
> application get drawn, the window then sits there for around 10s and
> the
> rest of the detail then gets filled in. Meanwhile, the task manager
> graphs
> have continued to scroll/update throughout.
> - The system remains 99% idle throughout the freeze. I don't see the
> CPU
> utilization go up and the winvnc4.exe process doesn't appear to grab
> any
> more cycles.
> - Pings from the client to the server remain at 1-2ms throughout the
> freeze.
> - The slow response remains regardless of which client machine or VNC
> client
> I connect from (i've tried realvnc and tightvnc clients on windows and
> linux
> hosts).
> - Restarting the VNC server process on the server doesn't help.
> - Raising the priority of the VNC server process doesn't help.
> - So far, rebooting the Win2k server is the only way I've been able to
> fix
> the problem.
>
> Cheers,
>
> Steve.
> _______________________________________________
> VNC-List mailing list
> VNC-List [at] realvnc
> To remove yourself from the list visit:
> http://www.realvnc.com/mailman/listinfo/vnc-list
_______________________________________________
VNC-List mailing list
VNC-List [at] realvnc
To remove yourself from the list visit:
http://www.realvnc.com/mailman/listinfo/vnc-list


stevelpub at gmail

Feb 19, 2009, 4:35 AM

Post #3 of 3 (1070 views)
Permalink
Re: Screen updates go slow after 2 weeks [In reply to]

Wez,

Thanks for the suggestions. I had a quick scan of windows events and memory
usage and didn't find anything unusual. None of the processes appeared to
be grabbing large chunks of memory or CPU. If it happens again, I'll try to
look more closely at the resource usage.

I did have quite a few applications running while this was happening and
started to close them down so I could reboot the system. Think I had closed
Word, Excel, Firefox and Acrobat Reader (not necessarily in that order) when
the system suddenly came back to life so I imagine the issue was related to
one of those applications. I still don't quite understand how one of those
apps could have caused the symptoms I was seeing (certain parts of another
application's window were freezing while other parts of it were updating
fine). I had assumed the VNC process or one of the sub-systems it relies on
was getting stuck.

Thanks for your help.

Steve.

On Mon, Feb 16, 2009 at 2:39 PM, James Weatherall <jnw [at] realvnc> wrote:

> Steve,
>
> Have you checked the memory usage of the server when it gets into this
> state? It's also worth checking the Windows event logs to see if there are
> any tell-tale errors from core OS components or drivers around the time the
> problem occurs. Finally, you can also check the number of handles that
> processes are holding via the Task Manager, which may help you determine
> whether it's a resource issue.
>
> Regards,
>
> --
> Wez @ RealVNC Ltd
>
>
> > -----Original Message-----
> > From: vnc-list-admin [at] realvnc [mailto:vnc-list-admin [at] realvnc] On
> > Behalf Of steve l
> > Sent: 12 February 2009 13:42
> > To: vnc-list [at] realvnc
> > Subject: Screen updates go slow after 2 weeks
> >
> > Hi all,
> >
> > I'm running VNC server 4.1.2 on a win2k server and have found that
> > screen
> > updates start to happen very slowly after having the server up for
> > around 2
> > weeks. I'm making fairly heavy use of VNC (I'm connected to the server
> > for
> > at least 4hrs per day). Any suggestions on how I can troubleshoot
> > this?
> > Some observations so far....
> >
> > - Its not a gradual performance degradation - the server goes straight
> > from
> > working fine to taking around 5-20s to update the screen - it's like
> > something breaks.
> > - This has happened 3 times so far and the system seems to fail after
> > (roughly) the same period of time.
> > - The delay only seems to occur on certain events...moving the mouse,
> > dragging windows, updating of counters/graphs within windows seems OK.
> > Changing the window focus (e.g. alt-tab) is a problem.
> > - Some of the time, the window gets partially drawn (usually the border
> > and
> > toolbars), then it freezes and the rest gets drawn (equally quickly)
> > after
> > the freeze.
> > - Not everything gets delayed - if I have Windows Task Manager set to
> > 'always on top' with the performance graphs showing & I change the
> > window
> > focus from one application to another, I see the borders of the new
> > application get drawn, the window then sits there for around 10s and
> > the
> > rest of the detail then gets filled in. Meanwhile, the task manager
> > graphs
> > have continued to scroll/update throughout.
> > - The system remains 99% idle throughout the freeze. I don't see the
> > CPU
> > utilization go up and the winvnc4.exe process doesn't appear to grab
> > any
> > more cycles.
> > - Pings from the client to the server remain at 1-2ms throughout the
> > freeze.
> > - The slow response remains regardless of which client machine or VNC
> > client
> > I connect from (i've tried realvnc and tightvnc clients on windows and
> > linux
> > hosts).
> > - Restarting the VNC server process on the server doesn't help.
> > - Raising the priority of the VNC server process doesn't help.
> > - So far, rebooting the Win2k server is the only way I've been able to
> > fix
> > the problem.
> >
> > Cheers,
> >
> > Steve.
> > _______________________________________________
> > VNC-List mailing list
> > VNC-List [at] realvnc
> > To remove yourself from the list visit:
> > http://www.realvnc.com/mailman/listinfo/vnc-list
>
>
_______________________________________________
VNC-List mailing list
VNC-List [at] realvnc
To remove yourself from the list visit:
http://www.realvnc.com/mailman/listinfo/vnc-list

VNC list RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.