Vivado simulator is hanging

Question

Hi,
I began to learn VHDL, because in the nearer future, I will program a FPGA. At first, I started with ISE. From a tutorial, I got this program: 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
entity TestLED is
    Port ( clk : in  STD_LOGIC;
           led : out  STD_LOGIC);
end TestLED;
architecture Behavioral of TestLED is
signal c:integer:=0;
signal x:STD_LOGIC:='0';
begin
    process begin
        wait until rising_edge(clk);
        if(c<24999998) then c <= c+1;
        else
            c <= 0;
            x <= not x;
        end if;
    end process;
    led <= x;       
end Behavioral;
ISE created this test bench:
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
ENTITY tb_TestLED IS
END tb_TestLED;
ARCHITECTURE behavior OF tb_TestLED IS
    -- Component Declaration for the Unit Under Test (UUT)
    COMPONENT TestLED
    PORT(
         clk : IN  std_logic;
         led : OUT  std_logic
    END COMPONENT;
   --Inputs
   signal clk : std_logic := '0';
     --Outputs
   signal led : std_logic;
   -- Clock period definitions
   constant clk_period : time := 10 ns;
BEGIN
    -- Instantiate the Unit Under Test (UUT)
   uut: TestLED PORT MAP (
          clk => clk,
          led => led
   -- Clock process definitions
   clk_process :process
   begin
        clk <= '0';
        wait for clk_period/2;
        clk <= '1';
        wait for clk_period/2;
   end process;
   -- Stimulus process
   stim_proc: process
   begin        
      -- hold reset state for 100 ns.
      wait for 100 ns;    
      wait for clk_period*10;
      -- insert stimulus here
      wait;
   end process;
END;
With the ISE simulator and a simulation time of 1 second, I quickly got my results. With Vivado 2015.2 and 64-bit Windows, I wasn't able to create automatically a test bench. So, I inserted the file which ISE created. Using the Vivado simulator, for some few hundred milliseconds, it needed a huge amount of time for the calculation. While this time my CPU usage was often at 0%. When I canceled the simulation, it did not stop and after a while I got a black window. So I had to shut down Vivado with my task manager. I still did not wait for Vivado to come to an end for an 1 second simulation. What's wrong with my programs, Vivado or with the configuration of Vivado?
Many greetings,
Andreas

Answer 1

Hi Bharath,
I think you misunderstood me. Running ISE and press "Run All", the simulation will run indefinitely. Doing the same with a simulation at Vivado, the simulation will stop after some hundreds milliseconds without any interactions from my side (CPU usage goes to 0%, the nanoseconds stop increasing, "Cancel" showes at the console, it was called, but the simulation does not end). So I found the strange behaviour, if I press "Zoom fit", it continues with the simulation. If I press something different than "Zoom Fit", it may occur that I get a black window and I have to shut down this application with the task manager. So, I come to the conclusion, there may be a bug at Vivado which relates to the graphics engine perhaps for special graphics cards (my adapter: AMD Radeon HD 7770) or there is something wrong with my system, what I still couldn't find out.
Many greetings,
Andreas