Decrease AC450 high load

AC450 high load

Hi stefan,

I have a redundant MB300 network consisting of 3 controllers ,2 of them are AC450 (Named ACA and ACB) , 1 SafeGuard 415 and 10 Operating Stations OS500 working under Unix .

The Controller ACA load is 55% (with a frequent spikes which reach 75%) and ACB load is 25% (with No Spikes). So my problem is how to decrease the load of ACA and decrease the Frequent Spikes in the Load?

So by check, I found that controller ACA Task Load DCTA200 (TTD Primary memory logging) is changing between 7 to 11% and DCTA500 (TTD Manipulation) is changing between 0 to 7% and DCTA600 (TTD Subscription) is changing between 2 to 4%.

So how can I decrease the load of the trend without deleting any trend?

Also I need to know the meaning Of TTD manipulation and TTD subscription which may help me in decreasing the load.

Best regards

Amr Hany

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amr hany Rank: 161

Asked 5 years ago

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The load dissipated by DCTAx00 is caused by TTD logging and HMI access to those logs.

The spikes are a natural behaviour. TTD tasks run with low priority and will not interfer with the controller's normal duties. In fact, "holes" in TTD trends is often debated at support - given the low prio, it is one of the things the controller will "drop" first if challenged by something else.

Only method to remove the spikes caused by DCTAx00 is to delete the logs.

55% average CPU load with "TTD-spikes" up to 75% is very far from overload - the Advant Controller 400 is very robust, even at 90% CPU load.

I would try other cleaning before chasing down TTD logs, eg unresolved symbols in OS500 stations (due to incorrect references in process displays) causing background load in CXNM200.

Replacing SC510 with SC520 carrier board will (if not already in place) more or less remove all load from CXNxxx (network tasks) off the main CPU.

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by amr hany Rank: 161 on 12/13/2015 12:25:27 PM | Like (0) | Report

Regarding the cxnm200
Tha aca controller has a sc520 with cs513 with address 7 and 8 (processing on main cpu)
so I am going to change this address to 4 and 5 (slave cpu processing) to be able to decrease the load.
So I expect that the load will decreade from 55% to 45%.is this right?
Also does this have any impact on the ttd log subscription?

by Rob Lyon Rank: 2 on 12/13/2015 7:22:32 PM | Like (0) | Report

> "Also does this have any impact on the ttd log subscription?"

No. TTD logging processes do not use the SC520 board.

> "So I expect that the load will decreade from 55% to 45%.is this right?"

Maybe, it depends how much of your CPU load is due to communications with other nodes on the MB300 ( or whatever the Submodules on those carrier boards are actually connected to )

At the risk of repeating myself, there is nothing wrong with your controller load right now. Your controller is actually quite lightly loaded. Modifying your controller configuration will give you no benefit at the risk of disturbing your controller.

Stefan Stromqvist AKS expert

Rank: 1 on 12/13/2015 10:55:16 PM | Like (0) | Report

> "So I expect that the load will decreade from 55% to 45%.is this right?"

The savings by substituting SC510 with SC520 and slaveNo < 7 is close to the sum of the CXNxxx tasks.

SC520 will also "isolate" the CPU from network storms that otherwise could cause CPU stall if long/powerful enough.

I repeat: 55% CPU with peaks up to 75% is very FAR from overload.

"Don't fix what's ain't broken"

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Stefan Stromqvist AKS expert

Rank: 1

Answered 5 years ago

A load of 75% CPU in an AC400 series controller is NOT high.

Spikes like this caused by TTD logging are absolutely normal. The DCTA tasks are a lower priority than the PC program interpreters and will timeout long before controller functions are affected.

Theres nothing wrong in what you describe - in fact your CPU load is quite low. The AC400 controller series can run at 80 - 90 % average CPU load with short spikes to 100% caused by TTD logging quite happily.

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Rob Lyon Rank: 2

Answered 5 years ago

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