Clients slower on WinCC OA 3.11 ??

[funkey]

Hello,
a few weeks ago we updated one scada system from 3.9 to 3.11. Now the operators told me, that the system is now slower than before. We have CPU loads from about 60% and more. Should I try to activate the 'messageCompression' option? And where in the config file do I get the most benefit with this option? We have a huge redundant system with more than 100000 datapoints.

Thanks for any information.

[Gertjan van Schijndel]

Message compression will probably only increase the cpu load. The number of datapoint is not a very good measurement of how large a system is, the number of value changes per second gives a better idea of how large the system is.

Do you know which process is causing the high cpu load?
To reduce the event managers load you can use the 'alertConditionBit' config entry.
To reduce the data managers load you can set '_last_value_storage_off' attribute (uncheck 'last value' in para) on polled addresses without alert handling.

[funkey]

Server cpu load is fine and I don't see how this settings can help reducing client cpu load. And I want default behaviour as it worked fine in previous versions of WinCC OA and I use the information in panels, which would be deactivated by this settings. I forgot to mention that especially switching between panels is much slower than before.

[Gertjan van Schijndel]

To my knowledge a panel becomes visible after the 'initialize' script(s) have been executed. When your code contains waiting dp-functions, it waits for a response from the server. And if your server is busy, it can take some time before the dp-message is processed. A cpu load of 25% on a quad core system for a single-core process (like the wincc oa managers) already means that the process is using all cpu power available.

When you disable the initialize script(s), does the switching between panels improve?
Did you only upgrade the wincc oa version? Or did you also upgrade the hardware/OS?

[funkey]

Initialize scripts are important, i cannot just deactivate them. Of course it would be faster if i did this. BTW most functions used in initialize scripts are dpConnect's.
As I mentioned the server cpu loads are fine (and as promised by Siemens / ETM). The only hardware thing we changed were the sas harddisks. The clients kept the same hardware and OS (WinXP x86 and Suse-Linux x86). We upgraded from 3.9 to 3.11

[leoknipp]

Hello,

if the CPU-load at the client does not decrease when loading and initializing the panels is finished the problem will not be caused by the initialize scripts.
If there is only a peak for the CPU-usage when switching the panels, the cause will be the execution of the initialize scripts.

Without detailled knowledge about your project and the current message traffic we cannot tell what the cause for the problem is.
To be able to analyze this problem in detail please get in contact with your common WinCC OA support.

Before releasing 3.11(+SP1) we made performance tests and compared the results with the previous versions. During these tests we have seen that an increasing performance of WinCC OA 3.11 compared to other versions.

Best Regards
Leopold Knipp
Senior Support Specialist