Worker Pools in Verilog

In this example, we’ll look at how to implement a worker pool using Verilog. Since Verilog is a hardware description language primarily used for modeling digital circuits, we’ll adapt the concept of worker pools to a digital design context.

module worker_pool;

  // Define parameters
  parameter NUM_WORKERS = 3;
  parameter NUM_JOBS = 5;
  
  // Define registers and wires
  reg clk;
  reg reset;
  reg [3:0] jobs [0:NUM_JOBS-1];
  wire [3:0] results [0:NUM_JOBS-1];
  wire [NUM_WORKERS-1:0] worker_busy;
  
  // Instantiate workers
  genvar i;
  generate
    for (i = 0; i < NUM_WORKERS; i = i + 1) begin : worker_gen
      worker w (
        .clk(clk),
        .reset(reset),
        .id(i),
        .job(jobs[i]),
        .result(results[i]),
        .busy(worker_busy[i])
      );
    end
  endgenerate
  
  // Controller logic
  reg [2:0] job_index;
  reg [2:0] result_index;
  
  always @(posedge clk or posedge reset) begin
    if (reset) begin
      job_index <= 0;
      result_index <= 0;
    end else begin
      // Assign jobs to available workers
      if (job_index < NUM_JOBS && !(&worker_busy)) begin
        jobs[job_index] <= job_index + 1;
        job_index <= job_index + 1;
      end
      
      // Collect results
      if (result_index < NUM_JOBS && !worker_busy[result_index % NUM_WORKERS]) begin
        $display("Result %d: %d", result_index, results[result_index]);
        result_index <= result_index + 1;
      end
    end
  end
  
  // Clock generation
  initial begin
    clk = 0;
    forever #5 clk = ~clk;
  end
  
  // Simulation
  initial begin
    reset = 1;
    #10 reset = 0;
    #200 $finish;
  end

endmodule

// Worker module
module worker (
  input clk,
  input reset,
  input [1:0] id,
  input [3:0] job,
  output reg [3:0] result,
  output reg busy
);

  reg [3:0] counter;
  
  always @(posedge clk or posedge reset) begin
    if (reset) begin
      busy <= 0;
      counter <= 0;
      result <= 0;
    end else begin
      if (!busy && job != 0) begin
        busy <= 1;
        counter <= 4'd10; // Simulate work duration
        $display("Worker %d started job %d", id, job);
      end else if (busy) begin
        if (counter == 0) begin
          busy <= 0;
          result <= job * 2; // Double the job number as the result
          $display("Worker %d finished job %d", id, job);
        end else begin
          counter <= counter - 1;
        end
      end
    end
  end

endmodule

In this Verilog implementation, we’ve created a worker pool system that simulates concurrent job processing. Here’s a breakdown of the code:

We define a worker_pool module that instantiates multiple worker modules.
The worker_pool module manages job distribution and result collection.
Each worker module simulates processing a job by counting down a delay and then producing a result.
The system uses a clock (clk) and reset signal to synchronize operations.

The main differences from the original Go example are:

Instead of using channels, we use registers and wires to communicate between modules.
The concept of goroutines is replaced with parallel instantiation of worker modules.
Job processing is simulated using a counter in each worker, rather than using actual time delays.
Results are displayed as they are produced, rather than collected at the end.

To run this Verilog simulation, you would typically use a Verilog simulator like ModelSim or Icarus Verilog. The simulation will show workers starting and finishing jobs, similar to the output of the original Go program.

This example demonstrates how concepts like worker pools can be adapted to hardware design languages, albeit with significant differences due to the nature of hardware description versus software programming.

Tickers in Verilog

Waitgroups in Verilog

Learn X By Example

Title here

Worker Pools in Verilog