Bus load analysis should take virtual buses into account

[lwrage]

Summary

The bus load analysis ignores virtual bus components. They should be treated like buses to allow partitioning of a physical bus into channels with their own bandwidth capacities.

Environment

• OSATE Version: 2.7.0
• Operating System: all

[AaronGreenhouse]

Is there an example of any sort for bus load analysis?

[AaronGreenhouse]

From @lwrage:

• The idea is that each (virtual) bus B has a bandwidth capacity and every connection or virtual bus bound to it consumes part of B. Obviously the sum must be less than B. This is for each (virtual) bus in the system.
• Now there is budgeting vs. actual. If 2 virtual buses are bound to a bus the sum of theis bandwidth capacities should be less than the bandwidth of the bus.
• Then there is the actual bandwidth needed by connections bound (directly or indirectly) to these 2 virtual buses. The sum of these actual demands must be less than the bandwidth of the bus. (Warning vs. error.)

This is similar to the weight budgets.

Note that a virtual bus A contained in another (virtual) bus B as a subcomponent is for this analysis equivalent to A being bound to B. (edited)

[AaronGreenhouse]

Need test cases:

• connections bound to a simple bus
  • simple connections
    • good (actual < budget < bus capacity)
    • warning (actual > budget, actual < bus capacity) (budget < actual < capacity)
    • bad (actual < budget, budget > bus capacity, actual < capacity)
    • bad (actual > budget, actual > bus capacity, budget < capacity)
    • bad (actual > budget, actual > bus capacity, budget > capacity)
  • Virtual bus
    • VB okay, fits on bus
      • VB as subcomponent
      • VB uses property association
    • VB overloaded, but VB fits on bus
      • VB as subcomponent
      • VB uses property association
    • VB overloaded, doesn't fit on bus
      • VB as subcomponent
      • VB uses property association
    • VB okay, but doesn't fit on bus
      • VB as subcomponent
      • VB uses property association

[AaronGreenhouse]

Whats the diff between SEI.Data_Rate and SEI.Message_Rate?

Also are they made obsolete by Communication_Properties.Output_Rate?

[AaronGreenhouse]

Never mind, I see OUTPUT_RATE is handled.

[AaronGreenhouse]

I'm confused about how or if feature groups are processed. I see code in calcBandwidthKBytesps() that looks for child features of features and checks that things make sense. But, how can this happen when we don't create feature group connections per se, but expand out all the connections.

[AaronGreenhouse]

There are currently "warnings" that appear in the report notes. Not all of these are reporting as warnings on the instance model. Should they be? In particular, there is not warning marker generated when a connection actual bandwidth is greater than the connection's budgeted bandwidth, but there is a note in the report.

[AaronGreenhouse]

First set of test cases

package Connections_Regular_Bus
public
	with SEI;

	data D1
		properties
			Data_Size => 8 Bytes;
	end D1;

	data D2
		properties
			Data_Size => 16 Bytes;
	end D2;

	data D3
		properties
			Data_Size => 24 Bytes;
	end D3;

	system S1
		features
			out1: out data port D1;
			in2: in data port D2;
			out3: out data port D3;
	end S1;

	system S2
		features
			in1: in data port D1;
			out2: out data port D2;
			in3: in data port D3;
	end S2;

	bus B
	end B;

	system Top
	end Top;

	system implementation Top.simple
		subcomponents
			sub1: system S1;
			sub2: system S2;
			theBus: bus B;
		connections
			conn1: port sub1.out1 -> sub2.in1 {
				Actual_Connection_Binding => (reference (theBus));
			};
			conn2: port sub2.out2 -> sub1.in2 {
				Actual_Connection_Binding => (reference (theBus));
			};
			conn3: port sub1.out3 -> sub2.in3 {
				Actual_Connection_Binding => (reference (theBus));
			};
	end Top.simple;

	system implementation Top.actualLessThanBudgetLessThanCapacity extends Top.simple
		properties
			-- Budgets 10, 20, 48
			-- Actuals 8, 16, 24

			-- Capacity 96
			-- total budget 78
			-- total actual 48			
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out1;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub2.out2;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out3;

			SEI::BandWidthBudget => 10.0 kbytesps applies to conn1;
			SEI::BandWidthBudget => 20.0 kbytesps applies to conn2;
			SEI::BandWidthBudget => 48.0 kbytesps applies to conn3;
			
			SEI::BandWidthCapacity => 96.0 kbytesps applies to theBus;				
	end Top.actualLessThanBudgetLessThanCapacity;

	system implementation Top.actualGreaterThanBudgetLessThanCapacity extends Top.simple
		properties
			-- Budgets 4, 20, 16
			-- Actuals 8, 16, 24

			-- Capacity 96
			-- total budget 40
			-- total actual 48			
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out1;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub2.out2;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out3;

			SEI::BandWidthBudget => 4.0 kbytesps applies to conn1;
			SEI::BandWidthBudget => 20.0 kbytesps applies to conn2; -- leave this one okay just for fun
			SEI::BandWidthBudget => 16.0 kbytesps applies to conn3;
			
			SEI::BandWidthCapacity => 96.0 kbytesps applies to theBus;				
	end Top.actualGreaterThanBudgetLessThanCapacity;

	system implementation Top.actualLessThanBudget_budgetGreaterThanCapacity_actualLessThanCapacity extends Top.actualLessThanBudgetLessThanCapacity
		properties
			-- Budgets 10, 20, 48
			-- Actuals 8, 16, 24

			-- Capacity 64
			-- total budget 78
			-- total actual 48			
			SEI::BandWidthCapacity => 64.0 kbytesps applies to theBus;				
	end Top.actualLessThanBudget_budgetGreaterThanCapacity_actualLessThanCapacity;

	system implementation Top.actualGreaterThanBudget_actualGreaterThanCapacity_budgetLessThanCapacity extends Top.simple
		properties
			-- Budgets 4, 20, 16
			-- Actuals 8, 16, 24

			-- Capacity 42
			-- total budget 40
			-- total actual 52			
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out1;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub2.out2;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out3;

			SEI::BandWidthBudget => 4.0 kbytesps applies to conn1;
			SEI::BandWidthBudget => 20.0 kbytesps applies to conn2; -- leave this one okay just for fun
			SEI::BandWidthBudget => 16.0 kbytesps applies to conn3;
			
			SEI::BandWidthCapacity => 42.0 kbytesps applies to theBus;				
	end Top.actualGreaterThanBudget_actualGreaterThanCapacity_budgetLessThanCapacity;

	system implementation Top.actualGreaterThanBudget_actualGreaterThanCapacity_budgetGreaterThanCapacity extends Top.simple
		properties
			-- Budgets 4, 20, 16
			-- Actuals 8, 16, 24

			-- Capacity 32
			-- total budget 40
			-- total actual 52			
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out1;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub2.out2;
			Communication_Properties::Output_Rate => [Value_Range => 800.0 .. 1000.0; Rate_Unit => PerSecond;] applies to sub1.out3;

			SEI::BandWidthBudget => 4.0 kbytesps applies to conn1;
			SEI::BandWidthBudget => 20.0 kbytesps applies to conn2; -- leave this one okay just for fun
			SEI::BandWidthBudget => 16.0 kbytesps applies to conn3;
			
			SEI::BandWidthCapacity => 32.0 kbytesps applies to theBus;				
	end Top.actualGreaterThanBudget_actualGreaterThanCapacity_budgetGreaterThanCapacity;
end Connections_Regular_Bus;

I noticed that if the actual bandwidths of the connections exceeds the budgeted bandwidths for the connections, and their total exceeds the bus capacity, there is of course an error. But what is not checked in this case if whether the total budgets for the connections also exceeds the bus capacity. I suppose you could argue that it is irrelevant at this point, but it seems like it should also be reported.