3.1 Network model
The suggested PABOM approach maps NoC using the balanced directive graph. The relationship between the two variables was analyzed using the mathematical model of weighted directed graph-based mapping.
Figure 2: weighted undirected graph
Considering Fig. 2, \(G=\left(V,E\right)\)is the formula for a weighted undirected graph, where "V" is the number of cores or vertices and "E" is the nodal connections. Five vertices constitute the undirected weighted directive graph as seen in Fig. 2\({\text{V}}_{1},{\text{V}}_{2},{\text{V}}_{3}, {\text{V}}_{4}, {\text{V}}_{5}\)eight edges make up the links\({\text{E}}_{1},{\text{E}}_{2},{\text{E}}_{3}, {\text{E}}_{4},{\text{E}}_{5},{\text{E}}_{6,}{\text{E}}_{7,}\text{E}8\). For each node \({\text{V}}_{1}\) in the network, we must identify the multi-objective Pareto functions, such as energy consumption, power, area, and latency for mapping. The node in the graph with the best fitness is heavier than the others. The following mathematical formula is used to map through the application of the injective map function in the graph theory,
$$F : {V}_{i} \to {V}_{j}$$
1
Here, \({V}_{i}\) and \({V}_{j}\) represent a network node, and F is the mapping function. Optimum resources are chosen for each node for multiobjective optimization. Resource energy consumption is given by (\({\phi }_{1}\)), area (\({\phi }_{2}\)), power \({(\phi }_{3}\)), and node latency ( \({\phi }_{4}\)). Meeting the conditions of Eq. (2) results in the best node selection. Binary mapping is used to locate neighboring nodes (i.e. minimum distance) and linkages.
$$P ({V}_{i},{V}_{j}) =\left\{\begin{array}{c}1 ; \text{arg}min \{ {\phi }_{1},{\phi }_{2},{\phi }_{3,}{\phi }_{4} \}\\ 0 ; otherwise \end{array}\right.$$
2
P (\({V}_{i}\), \({V}_{j}\) ) is the mapping probability function between the nodes. A node in the mapping function returns one if ideal and zero if not ideal. The Pareto Deming regressive African Buffalo Optimization mathematical model is covered in greater detail in the following sections.
3.2 Pareto Deming regressive African Buffalo Optimization model
The Pareto Deming regressive African Buffalo Optimization model was used to locate the optimal node. The African Buffalo Optimization meta-heuristic method was used to select the best buffalo from the population. The suggested optimization was inspired by the African woodland buffaloe optimization, which is more reliable and efficient than other optimization techniques because it requires fewer learning parameters and has a high convergence rate.
The different parametric functions of the Pareto optimization are: energy consumption \({\phi }_{1}\), area (\({\phi }_{2}\)), power \({(\phi }_{3}\)), and delay (\({\phi }_{4}\)). During the initialization phase of the algorithm, the buffalo populations are randomly initialized in the search space. Buffalo is connected to IP cores in this context. The initialization process is expressed as:
$${{C}_{i} \in {C}_{1},{C}_{2},{C}_{3},\dots C}_{\text{n}}$$
3
Where, \({C}_{i}\) denotes the IP cores. Then, the fitness is computed based on multiple objective functions of energy consumption (\({\phi }_{1}\)), Area (\({\phi }_{2}\)), power (\({\phi }_{3}\)), and delay (\({\phi }_{4})\).
The energy consumption is calculated using the following equation,
$${\phi }_{1}=\frac{{\varDelta t}_{i}}{{r}_{j}}$$
4
From (4), \({\phi }_{1}\) indicates energy consumed by module ‘\(i\)’, ‘\({\varDelta t}_{ij}\)’ represent the temperature rise at module‘\(i\)’ with respect to transfer resistance at module ‘\({r}_{j}\)’.
Area (\({\phi }_{2})\) is defined as a total area model 3D NoC is a sum of router/switch area (\({a}_{r})\), area of intellectual property (IP) cores (\({a}_{c})\) and area of on-chip global interconnects (\({a}_{g})\). The area is formulated as shown below,
$${\phi }_{2}={a}_{r}+{a}_{c}+{a}_{g}$$
5
$${a}_{r}=n*\sum _{i=1}^{{n}_{s}}{{a}_{r}}_{i}$$
6
Here, \(n\) is the number of planes presented in the 3D NoC, \({n}_{s}\) is the number of switches in the 2D or 3D network, \({{a}_{r}}_{i}\) is the area of switch\(i\). From (5), area of on-chip global interconnects ‘\({a}_{g}\)’ is measured using the equation,
$${a}_{g}={n}_{L}\left[f\left({r}_{w}+{q}_{w}\right)+{q}_{w}\right]{w}_{L}$$
7
Here, \({n}_{L}\) denotes the number of links presented in the 3D networks, \(f\) represents flit size in bits, \({r}_{w}\) denotes a wire width, \({q}_{w}\) indicates the spacing between wires, and \({w}_{L}\) is the wire length of the global interconnects in the on-chip network.
Power (\({\phi }_{3}\)), is a global link power and is the sum of the three different power consumptions of 3DNoC. It is given as,
$${p}_{g}={p}_{s}+{p}_{t}+{p}_{c}$$
8
Here, \({p}_{g}\) is global link power, \({p}_{s}\) is power due to circuit switching, \({p}_{t}\) is short circuit power, and \({p}_{c}\) denotes static power.
Delay (\({\phi }_{4})\) is measured using three factors, viz., router, propagation delay due to link or channel, and serialization of packets. The overall delay is measured as,
$$D={A}_{avg} R+{d}_{p}+{s}_{d}$$
9
Here \({A}_{avg}\)is the average hop count, R is the router, \({d}_{p}\) is propagation delay caused by link or channel, and \({s}_{d}\) is packet serialization. The Deming regression function is used for optimization, to examine the estimated values for each IP core's energy consumption (\({\phi }_{1}\)), area \(({\phi }_{2}\)), power (\({\phi }_{3}\)), and delay\({(\phi }_{4})\). Deming regression uses ML to examine the input variables and determine the population that best fits the input data. The regression analysis is shown below.
\({Y}_{i}={ \beta }_{0}+{ \beta }_{1} \left[{MC}_{k}\right({C}_{i}\left)\right]\)Where\({MC}_{k}\left({C}_{i}\right)\in {\phi }_{1},{\phi }_{2},{\phi }_{3},{\phi }_{4}\) (10)
Here, \({Y}_{i}\)is the output of the multiobjective estimation of the cores \({ C}_{i}\), \({ \beta }_{0}\) and \({ \beta }_{1}\) are regression coefficients, and \({MC}_{k}\left({C}_{i}\right)\) is the multiobjective estimation of the core. This includes the cores' energy consumption\(({\phi }_{1}\)), area\(({\phi }_{2}\)), power\({(\phi }_{3}\)), and delay\({(\phi }_{4})\). The node with lowest energy consumption, area utilization, power consumption, and delay is selected as the ideal one from the regression analysis. Fitness is then evaluated to determine the best-fitting IP core.
$${Q}_{F}=\text{arg}\text{min }\left\{{MC}_{k}\left({C}_{i}\right)\right\}$$
11
Here \({Q}_{F}\)is a fitness function and \(\text{arg}min\) for a minimum function's argument. The processes of exploration and exploitation are carried out based on the fitness value as in the following equation.
$${x}_{k}\left(t+1\right)={x}_{k}+ {a}_{1}\left[{{Q}_{F}}_{b}-{E}_{k}\right]+{a}_{2}\left[{x}_{bp}.k-{E}_{k}\right]$$
12
Here, \({x}_{k}\left(t+1\right)\)is the updated buffalos' exploitation of the ‘\(k\)’th buffalo,\({ x}_{k}\)is the \(k\)th buffalo's current position, \({E}_{k}\)is an exploration of the\({E}_{k} th\) buffalos, \({a}_{1}\) and\({a}_{2}\) are the learning parameters set values from 0.1 to 0.6, \({{Q}_{F}}_{b}\)is the best fitness of the buffalo's, and \({x}_{bp}\)The location of buffaloes is then updated as seen below.
$${E}_{k}\left(t+1\right)=\frac{\left[{E}_{k}+{x}_{k}\right]}{R }$$
13
From (13), \(R\) is a parameter value set as \(\pm\) 0.5, and \({E}_{k}\left(t+1\right)\) is the updated location of buffalos. Go back and update the buffalos if the convergence is not achieved; else, halt the procedure.
Figure 3 shows the Pareto Deming regressive African Buffalo Optimization flow process for determining the ideal IP core. Eq. (2) and the injective mapping function are used to calculate the mapping probability after locating the IP core. The ideal node is found when the mapping function returns a value of "1". The mapping function returns "0" in all other cases. The procedure is iterated until the maximum number of iterations. As a result, the 3D NoC chooses the optimum nearby core for direct communication.
The algorithmic process of the proposed PDRABOM method is described as follows.
// Algorithm 1 Pareto Deming Regressive African Buffalo Optimized mapping |
Input: Benchmark dataset, Number of cores \({{C}_{i} \in {C}_{1},{C}_{2},{C}_{3},\dots C}_{\text{n}}\) , Output: Find optimized IP core for NoC design |
Begin Step 1. Initialize the population of cores\({{C}_{i} \in {C}_{1},{C}_{2},{C}_{3},\dots C}_{\text{n}}\) Step 2. For each core\({C}_{i}\) Step 3. Compute multi-criteria function\({MC}_{k}\left({C}_{i}\right)\in {\phi }_{1},{\phi }_{2},{\phi }_{3},{\phi }_{4}\) Step 4. Measure the fitness ‘\({Q}_{F}\)’ Step 5. While (t < Max_ iter ) Step 6. if \(\left({Q}_{F}\left({C}_{i}\right)<{Q}_{F}\left({C}_{j}\right)\right)\) then Step 7. Update buffalos’ exploitation\({x}_{k}\left(t+1\right)\) Step 8. Update the location of buffalos\({E}_{k}\left(t+1\right)\) Step 9. End if Step 10. t = t + 1 Step 11. end while Step 12. Obtain the best solution Step 13. End For Step 14. Perform mapping \(F : {V}_{i} \to {V}_{j}\) based on probability\(P ({V}_{i},{V}_{j})\) End |
The Pareto Deming Regressive African Buffalo algorithm is described in detail in Algorithm 1 Optimized mapping for a more effective 3D NoC building design. The IP core populations in the search space are first initialized. The multicriteria function is then measured for each IP core in the population. The analysis of the multicriteria function then uses the Deming regression function. The best is chosen following the analysis of the fitness measure.
The position of ‘\(i\)’th buffalo is updated if the fitness of the current core, or \({ Q}_{F}\left({C}_{i}\right)\)is better than that of \({Q}_{F}\left({C}_{j}\right)\), The graphical model is then used to locate and map the current best core. The process is repeated until the number of iterations is reached. The mapping is performed based on probability. This method uses the least amount of time to perform an effective mapping of cores in the 3D NoC architecture.